External electrode forming device and external electrode forming method

Abstract

Provided is an external electrode forming device capable of forming an external electrode while suppressing variations in the application length of a conductive paste in an element body. An external electrode forming device 100 comprises a paste application table 10 in which are formed a planar flat surface part 12 and at least one paste filling hole 11 which is continuous with the flat surface part 12 and is recessed with respect to an upper surface 12a of the flat surface part 12, and into which a portion of an element body 42 of an electronic component is inserted. In the paste application table 10, a conductive paste 30 for forming an external electrode 50 on the element body 42 is filled in the paste filling hole 11 and the upper surface 12a of the flat surface part 12.

Description

External electrode forming device and external electrode forming method

[0001] The present invention relates to an external electrode forming apparatus and an external electrode forming method.

[0002] Patent Document 1 discloses an external electrode forming apparatus for forming external electrodes on the element body of an electronic component. The external electrode forming apparatus in Patent Document 1 has a casting table formed with a plurality of bottomed paste filling holes, which are filled with conductive paste. The element body is moved until it contacts the bottom of the paste filling hole and is immersed in the conductive paste. This applies the conductive paste to the element body.

[0003] Japanese Patent Application Publication No. 8-55766

[0004] When applying the conductive paste to the element body as described above, the element body may be immersed in the conductive paste in the paste filling hole with the center of the element body shifted from the center of the paste filling hole. If the element body is immersed in the conductive paste in such a shifted state, the length of the conductive paste applied to the element body may vary.

[0005] Therefore, a primary object of the present invention is to provide an external electrode forming apparatus and method that can form external electrodes while suppressing variations in the length of conductive paste applied to an element body.

[0006] The external electrode forming apparatus of the present invention comprises a paste application table having a planar surface portion and at least one paste filling hole that is continuous with the planar surface portion and recessed relative to the upper surface of the planar surface portion, into which a portion of an electronic component body is inserted, and the paste application table has a conductive paste filled into the paste filling hole and the upper surface of the planar surface portion for forming an external electrode on the body.

[0007] In the paste application table, conductive paste is filled not only in the paste filling holes but also on the upper surface of the flat portion continuous with the paste filling holes. A portion of the element body is inserted into the paste filling holes of the paste application table filled with conductive paste, and the conductive paste is applied to the element body. This prevents variation in the application length of the conductive paste applied to the element body (the application length is the length from the end face of the element body to the end of the conductive paste; hereinafter, simply referred to as "application length") even when the element body is immersed in the paste filling hole with its center misaligned with the center of the paste filling hole, and also prevents an increase in the standard deviation of the film thickness of the conductive paste on the end face of the element body.

[0008] According to the present invention, it is possible to provide an external electrode forming apparatus and an external electrode forming method that can form external electrodes while suppressing variations in the length of application of conductive paste on an element body.

[0009] The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention, which proceeds with reference to the accompanying drawings.

[0010] 1 is an external perspective view showing an example of a coil component as an electronic component according to an embodiment. FIG. 2 is a cross-sectional view of the coil component shown in FIG. 1 along line II-II. FIG. 3 is an exploded plan view of the coil component shown in FIG. 1. FIG. 4 is a cross-sectional view of the external electrode forming apparatus according to an embodiment, taken along line IV-IV in FIG. 5. FIG. 5 is a plan view of the external electrode forming apparatus shown in FIG. 4. (a) to (c) are cross-sectional views sequentially showing how conductive paste is applied to an element body using a paste application table. (b) to (c) are cross-sectional views showing a state in which an element body is immersed in conductive paste filled in a conventional paste application table. (a) to (c) are cross-sectional views showing an embodiment of an experiment according to a comparative example. (a) to (d) are cross-sectional views showing an embodiment of an experiment according to an example of the present invention. (c) are schematic views showing a method for measuring the standard deviation of film thickness and the difference in application length at the WT cross section. (d) is a schematic view ... comparative example No. 1 having no paste filling holes. 1A and 1B are schematic diagrams showing a state in which an element body is immersed in the conductive paste and then pulled up with the conductive paste filled on the top surface of a paste application table of Example No. 1, (a) is a schematic diagram showing the state of application of the conductive paste and the state of air getting in, and (b) is a schematic diagram showing the conductive paste and the flow rate of the air in shading. 1B are schematic diagrams showing a state in which an element body is immersed in the conductive paste and then pulled up with the conductive paste filled on the paste filling hole and the flat portion of a paste application table of Example No. 4 having a paste filling hole, (a) is a schematic diagram showing the state of application of the conductive paste and the state of air getting in, and (b) is a schematic diagram showing the conductive paste and the flow rate of the air in shading. 1C are cross-sectional views showing modified sidewall surfaces of the paste filling hole. 1D are cross-sectional views showing modified bottom surfaces of the paste filling hole. 1E are plan views of a paste application table relating to a modified example.

[0011] 1. Embodiments A coil component will be used as an example of an electronic component according to an embodiment of the present invention, and an external electrode forming apparatus for applying conductive paste to the element body of this coil component will be described.

[0012] (1) Coil Component Fig. 1 is an external perspective view showing an example of a coil component as an electronic component according to an embodiment. Fig. 2 is a cross-sectional view of the coil component shown in Fig. 1 taken along line II-II. Fig. 3 is an exploded plan view of the coil component shown in Fig. 1. The coil component 40 includes an element body 42, a coil 44 provided inside the element body 42, and an external electrode 50 provided on the surface of the element body 42 and electrically connected to the coil 44.

[0013] (1-1) Element Body The element body 42 is formed in a substantially rectangular parallelepiped shape. The element body 42 has a first main surface 42a and a second main surface 42b that face each other in a height direction x (stacking direction), a first side surface 42c and a second side surface 42d that face each other in a width direction y that is perpendicular to the height direction x, and a first end surface 42e and a second end surface 42f that face each other in a length direction z that is perpendicular to the height direction x and the width direction y. The element body 42 of this embodiment may have rounded corners and ridges. Note that a corner refers to a portion where three adjacent surfaces of the element body 42 intersect, and a ridge refers to a portion where two adjacent surfaces of the element body 42 intersect. Furthermore, unevenness or the like may be formed on some or all of the first main surface 42a and the second main surface 42b, the first side surface 42c and the second side surface 42d, and the first end surface 42e and the second end surface 42f.

[0014] The element body 42 includes a plurality of insulating layers 43. The insulating layers 43 are stacked in the height direction x. The insulating layers 43 are formed of, for example, a magnetic ferrite material. The magnetic ferrite material may include, for example, FeO, ZnO, CuO, or NiO. The insulating layers 43 may further include an additive such as, for example, MnO, CoO, SnO, BiO, or SiO.

[0015] (1-2) External Electrodes As shown in FIGS. 1 and 2, external electrodes 50 are disposed on the first end face 42e side and the second end face 42f side of the element body 42.

[0016] The external electrode 50 includes a first external electrode 50a and a second external electrode 50b.

[0017] The first external electrode 50a is disposed on at least the surface of the first end face 42e. In the present embodiment, the first external electrode 50a extends from the first end face 42e and is disposed on a part of the first principal face 42a, a part of the second principal face 42b, a part of the first side face 42c, and a part of the second side face 42d.

[0018] The second external electrode 50b is disposed on at least the surface of the second end face 42f. In the present embodiment, the second external electrode 50b extends from the second end face 42f and is disposed on a part of the first principal face 42a, a part of the second principal face 42b, a part of the first side face 42c, and a part of the second side face 42d.

[0019] (1-3) Coil The coil 44 is wound spirally along the height direction x. The coil 44 is made of a conductive material such as Ag or Cu. The coil 44 includes multiple coil conductors 44a, a first connecting conductor 44b, and a second connecting conductor 44c. The first connecting conductor 44b, the multiple coil conductors 44a, and the second connecting conductor 44c are arranged in order along the height direction x and are electrically connected in order via conductors. The multiple coil conductors 44a are connected in order along the height direction x to form a spiral shape along the height direction x. The first connecting conductor 44b is exposed from the first end face 42e of the element body 42 and connected to the first external electrode 50a. The second connecting conductor 44c is exposed from the second end face 42f of the element body 42 and connected to the second external electrode 50b.

[0020] (2) External Electrode Forming Apparatus Next, the external electrode forming apparatus 100 will be described. Fig. 4 is a cross-sectional view of an external electrode forming apparatus according to one embodiment, taken along line IV-IV in Fig. 5. Fig. 5 is a plan view of the external electrode forming apparatus shown in Fig. 4. Figs. 6(a) to 6(c) are cross-sectional views sequentially showing how conductive paste is applied to an element body using a paste application table. The external electrode forming apparatus 100 includes a paste application table 10 filled with conductive paste 30 for forming external electrodes 50. Furthermore, the external electrode forming apparatus 100 of this embodiment includes a holding device 20 for raising and lowering the element body 42 of the coil component 40 relative to the paste application table 10.

[0021] (2-1) Paste Application Table The paste application table 10 has a plurality of paste filling holes 11 and a plurality of flat portions 12. The flat portions 12 are formed in a planar shape and have upper surfaces 12a facing upward. The paste filling holes 11 are formed between adjacent flat portions 12, continuing into the flat portions 12 and recessed relative to the upper surfaces 12a of the flat portions 12. The paste filling holes 11 are formed to allow a portion of an element body 42 to be inserted therein. In this embodiment, the paste filling holes 11 are formed in a rectangular shape in cross section as shown in FIG. 4, and have a planar bottom surface 11a and a pair of planar sidewall surfaces 11b rising vertically upward from the ends of the bottom surface 11a. In this embodiment, the paste filling holes 11 are formed to extend elongatedly along the height direction x (predetermined direction) of the coil component 40, as shown in the plan view of FIG. 5, allowing a plurality of element bodies 42 to be inserted in parallel in the height direction x of the coil component 40. The number of paste filling holes 11 is not limited as long as it is one or more.

[0022] In the external electrode forming apparatus 100, the paste application table 10 is arranged with the bottom surfaces 11a of the paste filling holes 11 and the top surface 12a of the flat portion 12 facing upward. The paste application table 10 is prepared with the conductive paste 30 filled not only in the paste filling holes 11 but also on the top surface 12a of the flat portion 12. At this time, the paste thickness a of the conductive paste 30 is the thickness of the conductive paste 30 from the bottom surface 11a of the paste filling holes 11. The paste thickness a is the sum of the depth b of the paste filling holes 11 and the thickness c of the conductive paste 30 on the top surface 12a of the flat portion 12.

[0023] When applying conductive paste 30 to element body 42, element body 42 is lowered toward paste filling hole 11 until it contacts bottom surface 11a of paste filling hole 11, thereby immersing a portion of element body 42 in conductive paste 30. As shown in FIGS. 5 and 6(a), such paste filling hole 11 is formed so that length d of paste filling hole 11 in width direction y of coil component 40 is greater than length f (W dimension in this embodiment) of element body 42 in width direction y. Specifically, paste filling hole 11 is preferably formed so that, when element body 42 is inserted in paste filling hole 11, the distance between element body end 47 of element body 42 and hole end 11c of paste filling hole 11 is 10 μm or more and 1000 μm or less. In other words, the first distance Δg1 between first element body end 47a on the first side surface 42c side of element body 42 and first hole end 11c1 of paste filling hole 11 is preferably 10 μm or more and 1000 μm or less. Furthermore, the second distance Δg2 between the second element body end 47b on the second side surface 42d side of the element body 42 and the second hole end 11c2 of the paste filling hole 11 is preferably 10 μm or more and 1000 μm or less.

[0024] Furthermore, the length h of the upper surface 12a of the flat portion 12 in the width direction y is the length in the width direction y between adjacent paste filling holes 11. This length h is preferably designed so that, when the element body 42 is immersed in the paste filling hole 11, the conductive paste 30 that overflows from the paste filling hole 11 onto the upper surface 12a of the flat portion 12 can extend in a generally planar shape, as shown in Figure 6(a) . The length h is preferably, for example, not less than half the length d (½d) and not more than d.

[0025] Furthermore, with respect to the depth b of the paste filling hole 11 and the thickness c of the conductive paste 30 on the upper surface 12a of the flat portion 12, as the ratio of thickness c to paste thickness a increases, the standard deviation of the film thickness of the conductive paste 30 on the first end surface 42e (second end surface 42f) of the element body 42 tends to increase. Therefore, it is preferable that c / a, which is the ratio of thickness c to paste thickness a, be 0.7 or less. On the other hand, as the ratio of thickness c to paste thickness a decreases, the variation in the application length tends to increase. Therefore, it is preferable that c / a, which is the ratio of thickness c to paste thickness a, be 0.2 or more.

[0026] The conductive paste 30 contains a metal component. The metal component includes at least one selected from, for example, Ag, Au, Cu, Ni, Pd, Sn, Bi, or alloys containing these. Ag is used as the metal component because it has the lowest resistivity among metals, making it suitable as an electrode material, and because Ag is a noble metal, it does not oxidize and has high weather resistance. Metal powder coated with Ag can also be used as the metal component. When using Ag-coated metal powder, it is preferable to use Cu, Ni, Sn, Bi, or alloy powders thereof. The Ag-coated metal powder is used because it allows for the use of a cheaper base metal while maintaining the properties of Ag. The conductive paste 30 can also contain a glass component in addition to the metal component. The glass component includes at least one selected from B, Si, Ba, Mg, Al, Li, etc.

[0027] Furthermore, a conductive resin paste can be used as the conductive paste 30. The conductive resin paste contains, for example, a thermosetting resin and a metal component. The metal component is the same as described above. The thermosetting resin can be any of various known thermosetting resins, such as epoxy resin, phenoxy resin, phenol resin, urethane resin, silicone resin, and polyimide resin.

[0028] Furthermore, the conductive paste 30 preferably has a viscosity of 10 Pa·s or more and 60 Pa·s or less, a density of 2000 kg / m 3 or more and 3000 kg / m 3 or less, and a surface tension of 0.01 N / m or more and 0.04 N / m or less.

[0029] (2-2) Holding Device The holding device 20 holds the element body 42 so that the element body 42 can be inserted into the paste filling hole 11 of the paste applying table 10. The holding device 20 is arranged so that its lower surface 20a faces the surface of the paste applying table 10 on which the paste filling hole 11 is formed. The holding device 20 holds the element body 42 with a portion of the element body 42 protruding from the lower surface 20a at a position on the lower surface 20a facing the paste filling hole 11. In this embodiment, the holding device 20 holds the element body 42 with the entire first end surface 42e, a portion of the first side surface 42c, a portion of the second side surface 42d, a portion of the first main surface 42a, and a portion of the second main surface 42b exposed from the lower surface 20a. The first end surface 42e faces downward so as to face the paste filling hole 11. The number of element bodies 42 held by the holding device 20 is not limited, and may be one or more. The holding device 20 of this embodiment holds two or more element bodies 42 .

[0030] (3) Method for Forming External Electrodes Next, a method for forming external electrodes will be described.

[0031] 4, the paste application table 10 is prepared with the conductive paste 30 filled not only in the paste filling holes 11 but also on the upper surface 12a of the flat portion 12. The holding device 20 holds a plurality of element bodies 42 so that the first end surfaces 42e face the paste filling holes 11, and lowers the element bodies 42 toward the paste application table 10.

[0032] Next, as shown in FIG. 6( a), the first end surface 42e of the element body 42 is lowered to contact or near the bottom surface 11a of the paste filling hole 11, and a portion of the element body 42 is immersed in the conductive paste 30. At this time, the conductive paste 30 overflows from the paste filling hole 11 by the volume of the element body 42. As a result, the paste thickness of the conductive paste 30 increases by Δa, to a + Δa. It is believed that the overflowing conductive paste 30 is pulled by the conductive paste 30 on the upper surface 12a of the flat portion 12, and extends in a generally planar manner on the upper surface 12a of the flat portion 12. This prevents the overflowing conductive paste 30 from being applied to the element body 42 in a mounded state.

[0033] 6(b), the holding device 20 raises the element body 42 from the paste filling hole 11 while the conductive paste 30 is applied to the element body 42. The amount of conductive paste 30 in the paste filling hole 11 decreases by the amount of conductive paste 30 adhering to the element body 42. As a result, the conductive paste 30 filling the upper surface 12a of the flat portion 12 is drawn from the upper surface 12a of the flat portion 12 into the paste filling hole 11. At this time, the conductive paste 30 applied to the element body 42 is pulled by the conductive paste 30 drawn from the upper surface 12a of the flat portion 12 into the paste filling hole 11, forming an extended portion 30a.

[0034] 6(c), the holding device 20 further lifts the element body 42 out of the paste filling hole 11, separating the element body 42 from the conductive paste 30 on the paste application table 10. As a result, the conductive paste 30 is applied to the first end face 42e, part of the first main surface 42a, part of the second main surface 42b, part of the first side surface 42c, and part of the second side surface 42d of the element body 42.

[0035] Next, the element body 42 is held by the holding device 20 so that the second end surface 42f faces the paste application table 10. As described above, the element body 42 is immersed in the conductive paste 30 on the paste application table 10, whereby the conductive paste 30 is applied to the second end surface 42f, part of the first main surface 42a, part of the second main surface 42b, part of the first side surface 42c, and part of the second side surface 42d.

[0036] With the conductive paste 30 applied to the first end face 42 e, the second end face 42 f, part of the first main surface 42 a, part of the second main surface 42 b, part of the first side surface 42 c, and part of the second side surface 42 d, the element body 42 is fired at a temperature of approximately 800° C. This forms the first external electrode 50 a and the second external electrode 50 b. Note that the first external electrode 50 a and the second external electrode 50 b may be formed by forming a plating layer, such as a Ni plating layer or a Sn plating layer, on the fired conductive paste 30, thereby forming the first external electrode 50 a and the second external electrode 50 b, which include a base electrode layer made of the conductive paste 30 and a plating layer.

[0037] (4) Effects and Effects In the paste application table 10 described above, the conductive paste 30 is filled not only in the paste filling holes 11 but also on the upper surface 12a of the flat portion 12 that is continuous with the paste filling holes 11. A portion of the element body 42 is inserted into the paste filling holes 11 of the paste application table 10 that is filled with the conductive paste 30, and the conductive paste 30 is applied to the element body 42. As a result, even if the element body 42 is immersed in the paste filling holes 11 with the center of the element body 42 shifted from the center of the paste filling holes 11, it is possible to suppress variation in the application length of the conductive paste 30 applied to the element body 42 and to suppress an increase in the standard deviation of the film thickness of the conductive paste 30 on the first end face 42e (second end face 42f) of the element body 42. In the cross-sectional view of Figure 6 (c), the application length is application length e1 from the left end of the first end face 42e of the element 42 to the end of the conductive paste 30, and application length e2 from the right end of the first end face 42e of the element 42 to the end of the conductive paste 30.

[0038] The fact that variations in coating length can be suppressed and that an increase in the standard deviation of film thickness can be suppressed will be further explained as follows: Figure 7 is a cross-sectional view showing a state in which an element body is immersed in conductive paste filled in a conventional paste coating table.

[0039] 6A, when an element body 42 is inserted into the paste filling hole 11, the conductive paste 30 overflows from the paste filling hole 11 by the volume of the element body 42. It is thought that the overflowing conductive paste 30 is pulled by the conductive paste 30 on the upper surface 12a of the flat portion 12 and extends in a generally planar manner on the upper surface 12a of the flat portion 12. This prevents the overflowing conductive paste 30 from being applied to the element body 42 in a mounded state.

[0040] 7 , a conventional paste dispensing table 1B has paste filling holes 11 and a flat portion 12 formed therein, similar to the paste dispensing table 10 according to this embodiment. However, in the conventional paste dispensing table 1B, although the paste filling holes 11 are filled with conductive paste 30, the upper surface 12a of the flat portion 12 is not filled with conductive paste 30. In this case, when an element 42 is inserted into the paste filling holes 11, the conductive paste 30 overflows from the paste filling holes 11 onto the upper surface 12a of the flat portion 12 by an amount equal to the volume of the element 42, and the overflowing conductive paste 30 forms a raised portion 31 on the surface of the element 42 due to surface tension. If the element 42 is inserted into the paste filling holes 11 with the center of the element 42 misaligned with the center of the paste filling holes 11, and the overflowing conductive paste 30 forms a raised portion 31 on the surface of the element 42, the shape of the raised portion 31 will differ depending on the surface position of the element 42. In particular, the greater the deviation of the insertion position of element body 42 from the center of paste filling hole 11, the greater the variation in the shape of raised portion 31 depending on the surface position of element body 42. Therefore, the application length of conductive paste 30 varies depending on the surface position of element body 42. Furthermore, due to raised portion 31, conductive paste 30 is applied in a state that deviates from the required application length.

[0041] However, according to the configuration of the present embodiment described above, the conductive paste 30 that has overflowed from the paste filling hole 11 is prevented from being applied to the element body 42 in a mounded state, as shown in Figure 6 (a), and therefore, even if the element body 42 is inserted with its center offset from the center of the paste filling hole 11, variation in the application length of the conductive paste 30 on the element body 42 can be suppressed.

[0042] Furthermore, when the element body 42 is inserted into the paste filling hole 11, the conductive paste 30 in the paste filling hole 11 is applied to the element body 42. The element body 42 is then pulled up from the paste filling hole 11 with the conductive paste 30 applied. As shown in FIG. 6B , the conductive paste 30 filled on the upper surface 12a of the flat portion 12 is drawn from the upper surface 12a of the flat portion 12 into the paste filling hole 11 as the conductive paste 30 is pulled up together with the element body 42. At this time, the conductive paste 30 applied to the element body 42 is pulled by the conductive paste 30 drawn from the upper surface 12a of the flat portion 12 into the paste filling hole 11, causing the extending portion 30a of the conductive paste 30 extending from the first end face 42e (second end face 42f) of the element body 42 toward the paste filling hole 11 to become thinner. Here, by providing the paste filling holes 11, the absolute amount of conductive paste 30 applied to the element body 42 can be reduced compared to when the paste application table 10 is filled with conductive paste 30 without the paste filling holes 11. This also narrows the extension portions 30a of the conductive paste 30 extending from the first end face 42e (second end face 42f) of the element body 42 toward the paste filling holes 11. Therefore, the amount of conductive paste 30 applied to the first end face 42e (second end face 42f) of the element body 42 can be reduced, thereby preventing the standard deviation of the film thickness of the conductive paste 30 on the first end face 42e (second end face 42f) of the element body 42 from increasing. It is believed that an air flow flows toward the extension portions 30a between the conductive paste 30 applied to the element body 42 with the extension portions 30a and the conductive paste 30 drawn into the paste filling holes 11 from the upper surface 12a of the flat portion 12. It is believed that this air flow also narrows the extension portions 30a.

[0043] Furthermore, since the distance between element body end 47 of element body 42 and hole end 11c of paste filling hole 11 is set to be 10 μm or more and 1000 μm or less, variation in coating length can be suppressed and an increase in the standard deviation of film thickness can be suppressed. Specifically, when the distance between element body 42 and paste filling hole 11 is 10 μm or more and paste filling hole 11 becomes larger, the ratio of the volume of element body 42 to the amount of conductive paste 30 in paste filling hole 11 decreases. Therefore, when element body 42 is inserted into paste filling hole 11, the amount of conductive paste 30 that overflows is smaller than the amount of conductive paste 30 in paste filling hole 11. Therefore, combined with the action of the overflowing conductive paste 30 being pulled by the conductive paste 30 on upper surface 12a of flat portion 12, it is thought that the overflowing conductive paste 30 extends in a generally planar manner. This prevents the conductive paste 30 overflowing from the paste filling hole 11 from being applied to the element body 42 in a mounded state, thereby suppressing variations in the application length of the conductive paste 30 on the element body 42 even when the element body 42 is inserted with its center offset from the center of the paste filling hole 11. Furthermore, because the mounded state of the conductive paste 30 is suppressed, it is also possible to prevent the conductive paste 30 from being applied in a state that deviates from the required application length.

[0044] Furthermore, if the distance between the element body 42 and the paste filling hole 11 is 1000 μm or less, the absolute amount of conductive paste 30 applied to the element body 42 can be reduced. Therefore, when the element body 42 is pulled up from the paste filling hole 11 with the conductive paste 30 applied, the extension portion 30a extending from the first end face 42 e (second end face 42 f) of the element body 42 toward the paste filling hole 11 becomes thinner. Therefore, the amount of conductive paste 30 applied to the first end face 42 e (second end face 42 f) of the element body 42 can be reduced, and therefore the standard deviation of the film thickness of the conductive paste 30 on the first end face 42 e (second end face 42 f) of the element body 42 can be prevented from increasing.

[0045] 2. Experimental Example Next, an example of a numerical experiment including a comparative example and an example of the present invention will be specifically described. This numerical experiment was conducted using the external electrode formation device shown in FIG. 5. FIGS. 8(a) to 8(c) are cross-sectional views showing an example of an experiment related to a comparative example. FIGS. 9(a) to 9(d) are cross-sectional views showing an example of an experiment related to an example of the present invention. As a comparative example, an experiment was conducted using the embodiments of comparative examples No. 1 to No. 3 shown in FIGS. 8(a) to 8(c), respectively. Furthermore, as an example, an experiment was conducted using the embodiments of examples No. 4 to No. 7 shown in FIGS. 9(a) to 9(d), respectively.

[0046] In the experimental example, an element 42 was used in which the L dimension in the length direction z was L1 = 1.6 mm, the W dimension in the width direction y was W1 = 0.8 mm, and the T dimension in the height direction x was T1 = 0.8 mm. The conductive paste used had a viscosity of 50 Pa s, a density of 2700 kg / m3, and a surface tension of 0.02 N / m.

[0047] A. Experimental Mode (Comparative Example No. 1) An experiment was conducted using a conventional external electrode forming apparatus 1. As shown in FIG. 8( a), the paste application table 1A of the conventional external electrode forming apparatus 1 does not have a paste filling hole 11, unlike the paste application table 10 of this embodiment. The holding device 20 is the same as that of this embodiment and holds an element 42. The upper surface 1a of the paste application table 1A was filled with conductive paste 30 to a paste thickness a (=230 μm). The holding device 20 was lowered, so that the element 42 was immersed in the conductive paste 30 on the paste application table 1A. The holding device 20 was then raised, so that an element 42 coated with conductive paste 30 was obtained.

[0048] (Comparative Example No. 2) An experiment was conducted using a conventional external electrode forming apparatus 2. As shown in FIG. 8(b), the paste applying table 1B of the conventional external electrode forming apparatus 2 has paste filling holes 11 (length d = 1200 μm) and a flat portion 12, similar to the paste applying table 10 of this embodiment. However, unlike this embodiment, the upper surface 12a of the flat portion 12 was not filled with conductive paste 30, and the paste applying table 1B was prepared with only the paste filling holes 11 filled with conductive paste 30. The paste filling holes 11 were filled with conductive paste 30 to a depth b (= 230 μm). The paste thickness a was 230 μm. The holding device 20 held the element body 42 so that the center of the element body 42 coincided with the center of the paste filling holes 11. The first distance Δg1 between the first element body end 47a on the first side surface 42c side of the element body 42 and the first hole end 11c1 of the paste filling hole 11 was 200 μm, and the second distance Δg2 between the second element body end 47b on the second side surface 42d side of the element body 42 and the second hole end 11c2 of the paste filling hole 11 was 200 μm (Δg1 = Δg2). The element body 42 coated with the conductive paste 30 was obtained by moving the holding device 20 up and down.

[0049] (Comparative Example No. 3) As in Comparative Example No. 2, an experiment was conducted using a conventional external electrode forming apparatus 2. As in Comparative Example No. 2, the paste filling holes 11 were filled with conductive paste 30 to a paste thickness a (=230 μm). Comparative Example No. 3 differs from Comparative Example No. 2 in that the holding device 20 held the element body 42 in a state where the center of the element body 42 was offset from the center of the paste filling hole 11, as shown in FIG. 8(c). The first distance Δg1 was 300 μm, and the second distance Δg2 was 100 μm (Δg1 > Δg2). The holding device 20 was moved up and down to obtain an element body 42 coated with conductive paste 30.

[0050] (Example No. 4) An experiment was conducted using the external electrode forming apparatus 100 according to this embodiment. As shown in FIG. 9(a), a paste filling hole 11 (length d = 1200 μm, depth b1 = 150 μm) and a flat portion 12 were formed in the paste application table 10. The conductive paste 30 was filled into the paste filling hole 11 to its depth and to a thickness c1 (= 80 μm) on the upper surface 12a of the flat portion 12. The paste thickness a was 230 μm. The holding device 20 held the element body 42 so that the center of the element body 42 coincided with the center of the paste filling hole 11. The first distance Δg1 was 200 μm, and the second distance Δg2 was 200 μm (Δg1 = Δg2). The holding device 20 was moved up and down to obtain an element body 42 coated with the conductive paste 30.

[0051] Example 5 An experiment was conducted using the external electrode forming apparatus 100 according to the present embodiment. As shown in FIG. 9B, a paste filling hole 11 (length d = 1200 μm, depth b2 = 220 μm (b1 < b3 < b2)) and a flat portion 12 were formed in the paste application table 10. The conductive paste 30 was filled into the paste filling hole 11 to its depth, and was also filled on the upper surface 12a of the flat portion 12 to a thickness c2 (= 10 μm (c2 < c3 < c1)). The paste thickness a was 230 μm. The holding device 20 held the element body 42 with its center offset from the center of the paste filling hole 11. The first distance Δg1 was 300 μm, and the second distance Δg2 was 100 μm (Δg1 > Δg2). The holding device 20 was moved up and down to obtain an element body 42 coated with the conductive paste 30.

[0052] Example 6 An experiment was conducted using the external electrode forming apparatus 100 according to the present embodiment. As shown in FIG. 9C, a paste filling hole 11 (length d = 1200 μm, depth b3 = 200 μm (b1 < b3 < b2)) and a flat portion 12 were formed in the paste application table 10. The conductive paste 30 was filled into the paste filling hole 11 to its depth, and was also filled on the upper surface 12a of the flat portion 12 to a thickness c3 (= 30 μm (c2 < c3 < c1)). The paste thickness a was 230 μm. The holding device 20 held the element body 42 with its center offset from the center of the paste filling hole 11. The first distance Δg1 was 300 μm, and the second distance Δg2 was 100 μm (Δg1 > Δg2). The holding device 20 was moved up and down to obtain an element body 42 coated with the conductive paste 30.

[0053] (Example No. 7) An experiment was conducted using the external electrode forming apparatus 100 according to the present embodiment. As in Example No. 4, conductive paste 30 was filled to the paste filling hole 11 (length d = 1200 μm, depth b1 = 150 μm) to the depth thereof, and also filled to a thickness c1 (= 80 μm) on the upper surface 12a of the flat portion 12. The paste thickness a was 230 μm. Unlike Example No. 4, the holding device 20 held the element body 42 with the center of the element body 42 offset from the center of the paste filling hole 11. The first distance Δg1 was 300 μm, and the second distance Δg2 was 100 μm (Δg1 > Δg2). The holding device 20 was moved up and down to obtain an element body 42 coated with conductive paste 30.

[0054] B. Evaluation (a) Evaluation by Film Thickness Standard Deviation Figure 10 is a schematic diagram showing a method for measuring the film thickness standard deviation and the difference in coating length in a WT cross section. Figure 10 shows the end of the element body 42 on the first end face 42e side, to which the conductive paste 30 was applied. In the experimental example, the film thickness standard deviation was determined at the first end face 42e. The smooth end face was determined by subtracting the radius of curvature (r1 = 0.1) of both corners from the W dimension (W1 = 0.8 mm) of the first end face 42e, and the length of the smooth end face (W1 - 2 × r1 = 0.6 mm) was determined. In Figure 10, the smooth end face is the portion from position P1 to position P13. The interval between adjacent positions P1 to P13 was 5 mm. The film thickness of the conductive paste 30 at each of positions P1 to P13 in this smooth end face was determined. For example, at position P8, the film thickness of conductive paste 30 was determined as length t8 from the end of conductive paste 30 hanging down from first end face 42e to first end face 42e. Then, the film thickness standard deviation, which serves as an index of film thickness variation, was determined based on the film thickness of conductive paste 30 at each of positions P1 to P13.

[0055] (b) Evaluation by difference in coating length The coating length from the end of one side (left side in FIG. 10) of the first end face 42e of the element body 42 to the end of the conductive paste 30 was determined as coating length e1, and the coating length from the end of the other side (right side in FIG. 10) of the first end face 42e of the element body 42 to the end of the conductive paste 30 was determined as coating length e2. The difference in coating length was calculated as |e1-e2|. (c) Evaluation by c / a The ratio c / a of the thickness c of the conductive paste 30 on the upper surface 12a of the flat portion 12 to the paste thickness a was calculated.

[0056] Table 1 shows the results of c / a, paste shape at the end face, film thickness standard deviation, and coating length difference for No. 1 to No. 7.

[0057]

[0058] C. Results In Comparative Example No. 1, the paste application table 1A did not have paste filling holes 11, and the film thickness standard deviation was larger than in Comparative Examples No. 2 to No. 7. Meanwhile, the difference in application length was suppressed to 1 μm or less. Figure 11 is a schematic diagram showing the state in which the upper surface of a paste application table of Comparative Example No. 1, which does not have paste filling holes, is filled with conductive paste, and the element is immersed in the conductive paste and then lifted up. (a) is a schematic diagram showing the state of application of the conductive paste and the state of air infiltration, and (b) is a schematic diagram showing the conductive paste and air flow rate with shading. As shown in Figure 11(a), the extension portion 30a of the conductive paste 30 extending from the first end surface 42e of the element 42 toward the upper surface 1a of the paste application table 1A is formed over the entire first end surface 42e and is thick. As shown in Figure 11(b), although there is a flow of air 60 flowing toward the extension portion 30a between the conductive paste 30 applied to the base body 42 with the extension portion 30a and the conductive paste 30 drawn into the paste filling hole 11 from the upper surface 12a of the flat portion 12, the extension portion 30a has become thicker as described above.

[0059] In Comparative Example No. 2, the paste dispensing table 1B had paste filling holes 11, and only the paste filling holes 11 were filled with conductive paste 30. The film thickness standard deviation in Comparative Example No. 2 was smaller than that in Example No. 4, in which the paste filling holes 11 and the flat surface 12 of the paste dispensing table 10 according to the present embodiment were filled with conductive paste 30. The difference in coating length was also suppressed to 1 μm or less. However, when the paste dispensing table 1B of Comparative Example No. 2 was used and the element body 42 was immersed in conductive paste 30 with the center of the element body 42 misaligned with the center of the paste filling holes 11, as in Comparative Example No. 3, the difference in coating length was as large as 184 μm. The film thickness standard deviation in Comparative Example No. 3 was similar to that in Example No. 4 according to the present embodiment. Therefore, it was found that if the conductive paste 30 is filled only in the paste filling hole 11 and not in the flat portion 12, when the element body 42 is immersed in the conductive paste 30 and pulled up with the center of the element body 42 misaligned with the center of the paste filling hole 11, it is not possible to simultaneously suppress both the variation in the application length and the increase in the standard deviation of the film thickness.

[0060] In Example No. 4, in the paste dispensing table 10 according to the present embodiment, not only was the paste filling hole 11 (depth b1 = 150 μm) filled with conductive paste, but the flat portion 12 was also filled with conductive paste 30 (thickness c1 of the flat portion 12 = 80 μm) (paste thickness a = 230 μm). The standard deviation of film thickness in Example No. 4 was smaller than that in Comparative Example No. 1, and the difference in coating length was suppressed to 1 μm or less. Figure 12 is a schematic diagram showing the state in which an element body is immersed in conductive paste and then pulled up after the paste filling hole and flat portion are filled with conductive paste in a paste dispensing table of the type of Example No. 4 having a paste filling hole. (a) is a schematic diagram showing the state of application of the conductive paste and the state of air infiltration, and (b) is a schematic diagram showing the conductive paste and air flow rate in shading. As shown in FIG. 12( a), the extension 30a of the conductive paste 30 extending from the first end surface 42e of the element body 42 toward the bottom surface 11a of the paste filling hole 11 is smaller than the first end surface 42e and is therefore thinner. This is thought to be because the extension 30a is pulled by the conductive paste 30 drawn from the upper surface 12a of the flat portion 12 into the paste filling hole 11, and because it is restricted by the paste filling hole 11, the absolute amount of conductive paste 30 is reduced. Furthermore, as shown in FIG. 12( b), more air 60 flows toward the extension 30a, and the flow rate of the air 60 is faster than in FIG. 11( b), which is thought to result in the extension 30a being thinner. Therefore, it is thought that the amount of conductive paste 30 applied to the first end surface 42e of the element body 42 can be reduced, thereby preventing the standard deviation of the film thickness of the conductive paste 30 at the first end surface 42e of the element body 42 from increasing.

[0061] Furthermore, in Example No. 7, the same paste application table 10 (depth b1 = 150 μm, thickness c1 of flat portion 12 = 80 μm, paste thickness a = 230 μm) as in Example No. 4 was used, and element body 42 was immersed in conductive paste 30 with the center of element body 42 offset from the center of paste filling hole 11 in paste application table 10. In this case, the difference in application length was 15 μm, which was smaller than the 184 μm difference in application length in Comparative Example No. 3. Furthermore, the film thickness standard deviation in Example No. 7 was smaller than that of Comparative Example No. 1.

[0062] Furthermore, in Example No. 5, a paste application table 10 filled with conductive paste 30 (depth b2 = 220 μm, thickness c2 of flat portion 12 = 10 μm, paste thickness a = 230 μm) was used, and element body 42 was immersed in conductive paste 30 with the center of element body 42 offset from the center of paste filling hole 11 in paste application table 10. In this case, the difference in application length was 26 μm, which was smaller than the 184 μm difference in application length in Comparative Example No. 3. Furthermore, the film thickness standard deviation in Example No. 5 was smaller than that of Comparative Example No. 1.

[0063] Furthermore, in Example No. 6, a paste application table 10 filled with conductive paste 30 (depth b3 = 200 μm, thickness c3 of flat portion 12 = 30 μm, paste thickness a = 230 μm) was used, and element body 42 was immersed in conductive paste 30 with the center of element body 42 offset from the center of paste filling hole 11 in paste application table 10. In this case, the difference in application length was 23 μm, which was smaller than the difference in application length of 184 μm in Comparative Example No. 3. Furthermore, the standard deviation of film thickness in Example No. 6 was smaller than that in Comparative Example No. 1.

[0064] From the above, it was found that when the paste filling hole 11 and the flat portion 12 are filled with conductive paste 30 (Examples No. 4 to No. 7), even if the element body 42 is immersed in the conductive paste 30 and then pulled up with the center of the element body 42 misaligned with the center of the paste filling hole 11, it is possible to simultaneously suppress both the variation in the application length and the increase in the standard deviation of the film thickness.

[0065] According to Examples 4 to 7, c / a is preferably 0.13 or greater. Furthermore, c / a is even more preferably 0.345 or greater. When c / a is within this range, variation in coating length can be suppressed within a desired range, and the standard deviation of film thickness of conductive paste 30 on first end surface 42e of element body 42 can also be suppressed within a desired range.

[0066] 3. Modifications Although the embodiments of the present invention have been disclosed above, the present invention is not limited thereto. In other words, various modifications can be made to the above-described embodiments in terms of mechanism, shape, material, quantity, position, arrangement, etc., without departing from the scope of the technical idea and purpose of the present invention, and such modifications are included in the present invention.

[0067] (1) Sidewall Surface of Paste Filling Hole In the above embodiment, the sidewall surface 11b of the paste filling hole 11 is formed as a flat surface rising vertically upward from the end of the bottom surface 11a. However, the shape of the sidewall surface 11b is not limited to this, and the sidewall surface 11b may be formed so as to chamfer the corners of the paste filling hole 11. FIGS. 13(a) and 13(b) are cross-sectional views showing modified sidewall surfaces of the paste filling hole. For example, as shown in FIG. 13(a), the sidewall surface 11b may be formed as an inclined surface that slopes outward from the end of the bottom surface 11a upward. Furthermore, as shown in FIG. 13(b), the sidewall surface 11b may be formed as a curved surface that curves outward from the end of the bottom surface 11a upward. Alternatively, although not shown, the sidewall surface 11b may be formed as a curved surface that curves inward from the end of the bottom surface 11a upward.

[0068] This configuration further suppresses the increase in the standard deviation of the film thickness of the conductive paste 30 on the first end face 42e (second end face 42f) of the element body 42 and reduces the difference in the application length. When the element body 42 is pulled up from the paste filling hole 11, a flow of air 60 flows toward the extension 30a between the conductive paste 30 applied to the element body 42 with the extension 30a and the conductive paste 30 drawn into the paste filling hole 11 from the upper surface 12a of the flat portion 12. The flow velocity of this air 60 is thought to be increased by the fact that at least a portion of the side wall surface 11b of the paste filling hole 11 is curved or inclined. The increased flow velocity of the air 60 further narrows the extension 30a, thereby reducing the amount of conductive paste 30 applied to the first end face 42e (second end face 42f) of the element body 42. This suppresses the increase in the standard deviation of the film thickness and reduces the difference in the application length.

[0069] (2) Regarding the Bottom Surface of the Paste Filling Hole In the above embodiment, the bottom surface 11a of the paste filling hole 11 is flat. However, the shape of the bottom surface 11a is not limited to this. Fig. 14 is a cross-sectional view showing a modified example of the bottom surface of the paste filling hole. For example, as shown in Fig. 14, the bottom surface 11a may be formed with a bottom surface uneven portion 11a1 that is uneven relative to the bottom surface 11a.

[0070] The above configuration further prevents the standard deviation of the film thickness of the conductive paste 30 on the first end face 42e (second end face 42f) of the element body 42 from increasing, and also reduces the difference in application length. When the element body 42 is pulled up from the paste filling hole 11, air bubbles may enter the extension portion 30a of the conductive paste 30 extending from the first end face 42e (second end face 42f) of the element body 42 toward the paste filling hole 11, causing the extension portion 30a to become thicker. By forming the bottom surface unevenness 11a1 on the bottom surface 11a of the paste filling hole 11 as described above, it is believed that air bubbles are trapped in the bottom surface unevenness 11a1. Therefore, the entry of air bubbles into the extension portion 30a is prevented, thereby narrowing the extension portion 30a and reducing the amount of conductive paste 30 applied to the first end face 42e (second end face 42f) of the element body 42. Here, since the paste filling hole 11 is made smaller by the amount of the bottom surface unevenness 11a1, the absolute amount of conductive paste 30 applied to the element body 42 can be reduced. This also makes the extension portion 30a thinner. This prevents the film thickness standard deviation from becoming large, and makes it possible to reduce differences in application length.

[0071] (3) Planar Shape of Paste Filling Hole In the above embodiment, the planar shape of the paste filling hole 11 is formed to extend elongatedly along the height direction x of the coil component 40, as shown in FIG. 5 . However, the shape of the paste filling hole 11 is not limited to this. FIG. 15 is a plan view of a paste application table according to a modified example. For example, as shown in FIG. 15 , the paste filling hole 11 is formed so that when one element body 42 is inserted into the paste filling hole 11, the side wall surface of one paste filling hole 11 surrounds the one element body 42.

[0072] As described above, when one paste filling hole 11 is formed to surround one element body 42 inserted into that paste filling hole 11, the adhesive force of the conductive paste 30 is generally uniform around the entire circumference of the element body 42. This makes it possible to suppress variations in the length of the conductive paste 30 applied around the entire circumference of the element body 42. Furthermore, when the element body 42 with the conductive paste 30 applied thereto is pulled from the paste filling hole 11, the conductive paste 30 applied to the element body 42 is pulled from the entire circumference of the element body 42 by the conductive paste 30 drawn into the paste filling hole 11 from the upper surface 12a of the planar portion 12. This further narrows the extension portion 30a of the conductive paste 30 extending from the first end face 42e (second end face 42f) of the element body 42 toward the paste filling hole 11. This makes it possible to suppress an increase in the standard deviation of the film thickness of the conductive paste 30 at the first end face 42e (second end face 42f) of the element body 42.

[0073] The first distance Δg1 between the first element body end 47a on the first side surface 42c side of the element body 42 and the first hole end 11c1 of the paste filling hole 11 is preferably 10 μm or more and 1000 μm or less. The second distance Δg2 between the second element body end 47b on the second side surface 42d side of the element body 42 and the second hole end 11c2 of the paste filling hole 11 is preferably 10 μm or more and 1000 μm or less. Furthermore, the third distance Δg3 between the third element body end 47c on the first main surface 42a side of the element body 42 and the third hole end 11c3 of the paste filling hole 11 is preferably 10 μm or more and 1000 μm or less. Furthermore, a fourth distance Δg4 between a fourth element body end 47d on the second main surface 42b side of the element body 42 and a fourth hole end 11c4 of the paste filling hole 11 is preferably 10 μm or more and 1000 μm or less.

[0074] (4) Holding Device The external electrode forming apparatus 100 of the above embodiment is equipped with a holding device 20. However, as long as the element body 42 can be immersed in the conductive paste 30 on the paste application table 10, the holding device 20 may be omitted. For example, the coil component 40 may be manually immersed in the conductive paste 30 on the paste application table 10. In this case, the coil component 40 may be immersed manually in a state in which the coil component 40 is attached to an adhesive sheet or the like. Furthermore, the paste application table 10 may be moved up and down from below the coil component 40 in a state in which the coil component 40 is attached to the top surface with an adhesive sheet or the like.

[0075] (5) Regarding Electronic Components In the above embodiment, the coil component 40 has been given as an example of an electronic component. However, electronic components to which the present invention can be applied are not limited to the coil component 40, and examples thereof include capacitors, all-solid-state batteries, piezoelectric components, thermistor elements, and the like.

[0076] When a dielectric material is used for the insulating layer 43, the electronic component functions as a capacitor. Specific examples of the dielectric material include dielectric ceramics containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. When the dielectric material is used as the main component, a secondary component such as a manganese compound, an iron compound, a chromium compound, a cobalt compound, or a nickel compound may be added in a smaller amount than the main component, depending on the desired characteristics of the element body 42. Furthermore, when a piezoelectric ceramic material is used for the insulating layer 43, the electronic component functions as a piezoelectric component. Specific examples of the piezoelectric ceramic material include PZT (lead zirconate titanate)-based ceramic materials. Furthermore, when a semiconductor ceramic material is used for the insulating layer 43, the electronic component functions as a thermistor element. Specific examples of the semiconductor ceramic material include spinel-based ceramic materials.

[0077] <1> An external electrode forming apparatus comprising: a paste application table having a planar surface portion and at least one paste filling hole formed therein, the paste filling hole being continuous with the planar surface and recessed relative to an upper surface of the planar surface, and into which a portion of an electronic component body is inserted; wherein the paste application table is filled with a conductive paste for forming an external electrode on the body, the paste filling hole and the upper surface of the planar surface.

[0078] <2> The external electrode forming apparatus according to <1>, wherein the paste filling hole is formed so that the distance between the element body end portion of the element body inserted into the paste filling hole and the hole end portion of the paste filling hole adjacent to the element body end portion is 10 μm or more and 1000 μm or less.

[0079] <3> The external electrode forming device described in <1> or <2>, wherein the paste filling holes are formed to extend long in the predetermined direction so that multiple element bodies can be inserted in parallel in the predetermined direction, or the paste filling holes are formed so that the side wall surfaces of each paste filling hole surround each element body.

[0080] <4> The external electrode forming apparatus according to any one of <1> to <3>, wherein a ratio of the thickness of the conductive paste on the flat portion to the thickness of the conductive paste in the paste filling hole is 0.2 or more.

[0081] <5> The external electrode forming apparatus according to any one of <1> to <4>, wherein at least a part of a side wall surface of the paste filling hole is formed into a curved or inclined surface.

[0082] <6> The external electrode forming apparatus according to any one of <1> to <5>, wherein a bottom surface uneven portion having an uneven shape relative to the bottom surface of the paste filling hole is formed on the bottom surface of the paste filling hole.

[0083] <7> The external electrode forming apparatus according to any one of <1> to <6>, wherein the conductive paste contains at least one of silver, gold, and copper.

[0084] <8> A method for forming an external electrode using an external electrode forming device, comprising: a paste application table having a planar portion; and at least one paste filling hole formed therein, the paste filling hole being continuous with the planar portion and recessed relative to an upper surface of the planar portion, into which a portion of an electronic component body is inserted, the paste application table being filled with a conductive paste for forming an external electrode on the body, the paste filling hole and the upper surface of the planar portion, the method comprising: a step of lowering at least one of the body bodies toward the paste filling hole, thereby immersing the body in the conductive paste; and a step of raising the body out of the paste filling hole with the conductive paste applied to the body.

[0085] <9> The method for forming an external electrode according to <8>, wherein the paste filling hole is formed so that the distance between an end of the element body inserted into the paste filling hole and an end of the paste filling hole adjacent to the end of the element body is 10 μm or more and 1000 μm or less.

[0086] <10> The method for forming an external electrode according to <8> or <9>, wherein the paste filling hole is formed to extend long in the predetermined direction so that a plurality of the element bodies can be inserted in parallel in the predetermined direction, or the paste filling hole is formed so that the side wall surface of each paste filling hole surrounds each element body.

[0087] <11> The external electrode forming method according to any one of <8> to <10>, wherein a ratio of the thickness of the conductive paste on the flat portion to the thickness of the conductive paste in the paste filling hole is 0.2 or more.

[0088] <12> The method for forming an external electrode according to any one of <8> to <11>, wherein at least a part of a side wall surface of the paste filling hole is formed into a curved or inclined surface.

[0089] <13> The method for forming an external electrode according to any one of <8> to <12>, wherein a bottom surface uneven portion having an uneven shape relative to the bottom surface of the paste filling hole is formed on the bottom surface of the paste filling hole.

[0090] <14> The method for forming an external electrode according to any one of <8> to <13>, wherein the conductive paste contains at least one of silver, gold, and copper.

[0091] DESCRIPTION OF SYMBOLS 1, 2, 100: External electrode forming apparatus 1A, 1B, 10: Paste application table 1a: Upper surface 11: Paste filling hole 11a: Bottom surface 11a1: Bottom surface uneven portion 11b: Side wall surface 11c: Hole end 11c1 to 11c4: First to fourth hole end 12: Flat portion 12a: Upper surface 20: Holding device 20a: Lower surface 30: Conductive paste 30a: Extension portion 31: Protrusion portion 40: Coil component 42: Element body 42a, 42b: First and second main surfaces 42c, 42d: First and second side surfaces 42e, 42f: First and second end surfaces 43: Insulating layer 44: Coil 44a: Coil conductor 44b : First connecting conductor 44c : Second connecting conductor 47 : End portion of element body 47a to 47d : First to fourth end portions of element body 50 : External electrode 50a, 50b : First and second external electrodes x : Height direction y : Width direction z : Length direction

Claims

1. a paste applying table having a flat surface portion and at least one paste filling hole formed therein, the paste filling hole being continuous with the flat surface portion and recessed with respect to an upper surface of the flat surface portion, and into which a part of an element body of an electronic component is inserted; a conductive paste for forming external electrodes on the element body is filled into the paste filling holes and an upper surface of the flat portion on the paste application table; The thickness of the conductive paste in the paste filling hole is: the thickness of the conductive paste on the upper surface of the flat portion is greater than the thickness of the conductive paste on the upper surface of the flat portion External electrode forming device.

2. 2. The external electrode forming apparatus of claim 1, wherein the paste filling hole is formed so that the distance between the element body end of the element body inserted into the paste filling hole and the hole end of the paste filling hole adjacent to the element body end is 10 μm or more and 1000 μm or less.

3. 3. The external electrode forming device as described in claim 1 or 2, wherein the paste filling hole is formed to extend long in the predetermined direction so that a plurality of the element bodies can be inserted in parallel in the predetermined direction, or the paste filling hole is formed so that the side wall surface of each paste filling hole surrounds each element body.

4. 3. The external electrode forming apparatus according to claim 1, wherein a ratio of a thickness of the conductive paste on the flat portion to a thickness of the conductive paste in the paste filling hole is 0.2 or more.

5. 3. The external electrode forming apparatus according to claim 1, wherein at least a part of a side wall surface of the paste filling hole is formed into a curved or inclined surface.

6. 3. The external electrode forming apparatus according to claim 1, wherein a bottom surface of the paste filling hole has an uneven portion having an uneven shape relative to the bottom surface of the paste filling hole.

7. 3. The external electrode forming apparatus according to claim 1, wherein the conductive paste contains at least one of silver, gold, and copper.

8. a paste applying table having a flat surface portion and at least one paste filling hole formed therein, the paste filling hole being continuous with the flat surface portion and recessed with respect to an upper surface of the flat surface portion, and into which a part of an element body of an electronic component is inserted; a conductive paste for forming external electrodes on the element body is filled into the paste filling holes and the upper surface of the flat portion on the paste application table; The thickness of the conductive paste in the paste filling hole is: the thickness of the conductive paste on the upper surface of the flat portion is greater than the thickness of the conductive paste on the upper surface of the flat portion A method for forming an external electrode using an external electrode forming apparatus, comprising the steps of: dipping at least one of the bodies into the conductive paste by lowering the body toward the paste filling hole; and lifting the element body with the conductive paste applied thereto out of the paste filling hole.

9. 9. The method for forming an external electrode as described in claim 8, wherein the paste filling hole is formed so that the distance between the element body end portion of the element body inserted into the paste filling hole and the hole end portion of the paste filling hole adjacent to the element body end portion is 10 μm or more and 1000 μm or less.

10. The method for forming an external electrode as described in claim 8 or 9, wherein the paste filling hole is formed to extend long in the predetermined direction so that a plurality of the element bodies can be inserted in parallel in the predetermined direction, or the paste filling hole is formed so that the side wall surface of each paste filling hole surrounds each element body.

11. 10. The method for forming an external electrode according to claim 8, wherein a ratio of a thickness of the conductive paste on the flat portion to a thickness of the conductive paste in the paste filling hole is 0.2 or more.

12. 10. The method for forming an external electrode according to claim 8, wherein at least a part of a side wall surface of the paste filling hole is formed into a curved or inclined surface.

13. 10. The method for forming an external electrode according to claim 8, wherein a bottom surface uneven portion having an uneven shape relative to the bottom surface of the paste filling hole is formed on the bottom surface of the paste filling hole.

14. 10. The method for forming external electrodes according to claim 8, wherein the conductive paste contains at least one of silver, gold, and copper.