Electronic component

Abstract

A glass film (50) has a base part (51) and a specific part (52). The base part (51) contains, in addition to silicon oxide, an oxide of at least one metal element from among alkali metals and alkaline-earth metals. The specific part (52) contains, in addition to silicon oxide, an oxide of the same metal element as that in the base part (51). The contained proportion of the metal element in the specific part (52) is smaller than the contained proportion of the metal element in the base part (51).

Description

Technical Field

[0001] The present invention relates to electronic components.

Background Art

[0002] Patent Document 1 describes an electronic component. The electronic component includes a body and external electrodes laminated on the surface of the body. The external electrodes are formed by baking a conductive paste. The conductive paste contains conductive powder, borosilicate glass, silica powder, and an organic vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The electronic component described in Patent Document 1 contains silica powder in the external electrodes. Therefore, the resistance to a water-soluble flux, which is a surface treatment agent during soldering, i.e., so-called flux resistance, can be improved. On the other hand, since the conductive paste in the electronic component described in Patent Document 1 contains silica powder at a high concentration, the melting point of the conductive paste becomes high. Therefore, cracks are likely to occur in the body or the like during the baking of the conductive paste. Therefore, there is a limit to increasing the amount of silica powder. Therefore, a technique capable of improving the flux resistance is required separately from the addition of silica powder.

Means for Solving the Problems

[0005] To solve the above problems, one aspect of the present disclosure provides an electronic component including a base body, a glass film covering the outer surface of the base body, and an external electrode provided on the outer surface of the glass film and having at least a base electrode. The glass film has a base portion containing an oxide of at least one metal element among alkali metals and alkaline earth metals in addition to silicon oxide, and a specific portion containing an oxide of the same metal element as the base portion in addition to silicon oxide. The content ratio of the metal element in the specific portion is smaller than the content ratio of the metal element in the base portion.

[0006] According to the above configuration, an interface between the base portion and the specific portion can be formed in the glass film. When an interface exists in the glass film in this way, even if a water-soluble flux penetrates into the glass film, although the water-soluble flux extends on the interface, it is difficult to penetrate deeper. Therefore, erosion from the outside to the base body can be further prevented.

Advantages of the Invention

[0007] The flux resistance can be improved.

Brief Description of the Drawings

[0008]

Figure 1

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Figure 10

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Figure 12

DETAILED DESCRIPTION OF THE INVENTION

[0009] (One Embodiment) Hereinafter, an embodiment of an electronic component will be described with reference to the drawings. Note that the drawings may show components enlarged for ease of understanding. The dimensional ratios of the components may be different from the actual ones or those in other drawings.

[0010] <Schematic Configuration of Electronic Component> As shown in FIG. 1, the electronic component 10 is, for example, a surface-mount negative characteristic thermistor component mounted on a circuit board or the like. Note that the negative characteristic thermistor component has a characteristic that the resistance value decreases as the temperature increases.

[0011] The electronic component 10 includes a body 20. The body 20 is substantially quadrangular prism-shaped and has a central axis CA. Hereinafter, the axis extending along the central axis CA is defined as the first axis X. One of the axes orthogonal to the first axis X is defined as the second axis Y. And the axis orthogonal to the first axis X and the second axis Y is defined as the third axis Z. Further, one of the directions along the first axis X is defined as the first positive direction X1, and the direction opposite to the first positive direction X1 among the directions along the first axis X is defined as the first negative direction X2. Also, one of the directions along the second axis Y is defined as the second positive direction Y1, and the direction opposite to the second positive direction Y1 among the directions along the second axis Y is defined as the second negative direction Y2. Further, one of the directions along the third axis Z is defined as the third positive direction Z1, and the direction opposite to the third positive direction Z1 among the directions along the third axis Z is defined as the third negative direction Z2.

[0012] The outer surface 21 of the body 20 has six planes 22. Here, the "surface" of the body 20 refers to what can be observed as a surface when observing the entire body 20. That is, for example, even if there are minute irregularities or steps that cannot be understood without magnifying and observing a part of the body 20 with a microscope or the like, it is expressed as a flat surface or a curved surface. The six planes 22 extend in different directions from each other. The six planes 22 are roughly classified into a first end face 22A facing the first positive direction X1, a second end face 22B facing the first negative direction X2, and four side faces 22C. Each of the four side faces 22C is a face facing the third positive direction Z1, a face facing the third negative direction Z2, a face facing the second positive direction Y1, and a face facing the second negative direction Y2.

[0013] The outer surface 21 of the body 20 has twelve boundary surfaces 23. The boundary surfaces 23 include curved surfaces existing at the boundaries between adjacent planes 22. That is, the boundary surfaces 23 include, for example, curved surfaces formed by chamfering the corners formed by adjacent planes 22 with an R chamfer.

[0014] Also, the outer surface 21 of the body 20 has eight spherical corner surfaces 24. The corner surfaces 24 are boundary portions between three adjacent planes 22. In other words, the corner surfaces 24 include curved surfaces at the locations where three boundary surfaces 23 intersect. That is, the corner surfaces 24 include, for example, curved surfaces formed by chamfering the corners formed by three adjacent planes 22 with an R chamfer.

[0015] In FIGS. 1 and 2, the surface of the glass film 50 described later is regarded as the same as the outer surface 21 of the body 20 and is labeled with the same reference numerals. As shown in FIG. 2, the dimension of the body 20 in the direction along the first axis X is larger than the dimension in the direction along the third axis Z. Also, as shown in FIG. 1, the dimension of the body 20 in the direction along the first axis X is larger than the dimension in the direction along the second axis Y. Further, the material of the body 20 is ceramics obtained by firing a metal oxide containing at least one of Mn, Fe, Ni, Co, Ti, Ba, Al, and Zn as a component.

[0016] As shown in FIG. 3, the electronic component 10 includes two first internal electrodes 41 and two second internal electrodes 42. The first internal electrodes 41 and the second internal electrodes 42 are embedded inside the base body 20.

[0017] The material of the first internal electrode 41 is a conductive material. For example, the material of the first internal electrode 41 is silver and palladium. Also, the material of the second internal electrode 42 is the same silver and palladium as the material of the first internal electrode 41.

[0018] The shape of the first internal electrode 41 is a rectangular plate shape. The main surface of the first internal electrode 41 is orthogonal to the second axis Y. The shape of the second internal electrode 42 is the same rectangular plate shape as the first internal electrode 41. The main surface of the second internal electrode 42 is orthogonal to the second axis Y, similar to the first internal electrode 41.

[0019] The dimension of the first internal electrode 41 in the direction along the first axis X is smaller than the dimension of the base body 20 in the direction along the first axis X. Also, as shown in FIG. 1, the dimension of the first internal electrode 41 in the direction along the third axis Z is approximately two-thirds of the dimension of the base body 20 in the direction along the third axis Z. The dimensions of the second internal electrode 42 in each direction are the same as those of the first internal electrode 41.

[0020] As shown in FIG. 3, the first internal electrode 41 and the second internal electrode 42 are alternately positioned in the direction along the second axis Y. That is, from the side surface 22C facing the second positive direction Y1 to the second negative direction Y2, the first internal electrode 41, the second internal electrode 42, the first internal electrode 41, and the second internal electrode 42 are arranged in this order. In this embodiment, the distances in the direction along the second axis Y between the respective internal electrodes are equal.

[0021] As shown in FIG. 1, both of the two first internal electrodes 41 and the two second internal electrodes 42 are positioned at the center of the base body 20 in the direction along the third axis Z. On the other hand, as shown in FIG. 3, the first internal electrode 41 is positioned closer to the first positive direction X1. The second internal electrode 42 is positioned closer to the first negative direction X2.

[0022] Specifically, the end of the first internal electrode 41 on the first positive direction X1 side coincides with the end of the base body 20 on the first positive direction X1 side. The end of the first internal electrode 41 on the first negative direction X2 side is located inside the base body 20 and does not reach the end of the base body 20 on the first negative direction X2 side. On the other hand, the end of the second internal electrode 42 on the first negative direction X2 side coincides with the end of the base body 20 on the first negative direction X2 side. The end of the second internal electrode 42 on the first positive direction X1 side is located inside the base body 20 and does not reach the end of the base body 20 on the first positive direction X1 side.

[0023] The electronic component 10 includes a glass film 50. The glass film 50 covers the outer surface 21 of the base body 20. In this embodiment, the glass film 50 covers substantially all regions of the outer surface 21 of the base body 20. The main material of the glass film 50 is insulating glass. Therefore, the glass film 50 contains silicon oxide, specifically silicon dioxide.

[0024] As shown in FIG. 3, the electronic component 10 includes a first external electrode 61 and a second external electrode 62. The first external electrode 61 has a first base electrode 61A and a first metal layer 61B. The first base electrode 61A is laminated on the glass film 50 in a part of the outer surface 21 of the base body 20 including the first end face 22A. Specifically, the first base electrode 61A is a five-sided electrode that covers the first end face 22A of the base body 20 and a part of the first positive direction X1 side of the four side faces 22C. In this embodiment, the material of the first base electrode 61A is copper.

[0025] The first metal layer 61B covers the first base electrode 61A from the outside. Therefore, the first metal layer 61B is laminated on the first base electrode 61A. Specifically, as shown in FIG. 4, the first metal layer 61B has a two-layer structure of a nickel layer 61C and a tin layer 61D. Also, as shown in FIG. 3, the outer edge of the first metal layer 61B is located outside the outer edge of the first base electrode 61A. And the outer edge of the first metal layer 61B is located on the surface of the glass film 50. Therefore, a part of the first metal layer 61B is located on the surface of the glass film 50.

[0026] As shown in FIG. 3, the second external electrode 62 has a second base electrode 62A and a second metal layer 62B. The second base electrode 62A is laminated on the glass film 50 from above at a part of the outer surface 21 of the element body 20 including the second end face 22B. Specifically, the second base electrode 62A is a five-sided electrode that covers the second end face 22B of the element body 20 and a part of the first negative direction X2 side of the four side faces 22C. In this embodiment, the material of the second base electrode 62A is the same as that of the first external electrode 61, which is copper.

[0027] The second metal layer 62B covers the second base electrode 62A from the outside. Therefore, the second metal layer 62B is laminated on the second base electrode 62A. Specifically, the second metal layer 62B has a two-layer structure of a nickel layer and a tin layer, although not shown, similar to the first metal layer 61B. Further, as shown in FIG. 3, the outer edge of the second metal layer 62B is located outside the outer edge of the second base electrode 62A. And the outer edge of the second metal layer 62B is located on the surface of the glass film 50. Therefore, a part of the second metal layer 62B is located on the surface of the glass film 50.

[0028] The second external electrode 62 does not reach the first external electrode 61 on the side face 22C and is arranged apart from the first external electrode 61 in the direction along the first axis X. And in the central part in the direction along the first axis X on the side face 22C of the element body 20, neither the first external electrode 61 nor the second external electrode 62 is laminated, and the glass film 50 is exposed. In FIGS. 1 to 3, the first external electrode 61 and the second external electrode 62 are illustrated by a two-dot chain line.

[0029] As shown in FIG. 3, the end on the first positive direction X1 side of the first external electrode 61 and the first internal electrode 41 are connected through a first through portion 71 that penetrates the glass film 50. Although details will be described later, the first through portion 71 is formed by the silver and palladium constituting the first internal electrode 41 extending toward the first external electrode 61 side in the manufacturing process of the electronic component 10.

[0030] Further, the second external electrode 62 and the ends on the first negative direction X2 side of the second internal electrode 42 are connected via a second through-hole 72 that penetrates the glass film 50. Similar to the first through-hole 71, the second through-hole 72 is formed by silver and palladium that constitute the second internal electrode 42 extending toward the second external electrode 62 side during the manufacturing process of the electronic component 10. In FIG. 3, the first internal electrode 41 and the first through-hole 71 are illustrated as separate members with a boundary therebetween, but actually there is no clear boundary between the two. This also applies to the second through-hole 72. Also, in FIGS. 1 and 2, the illustration of the first through-hole 71 and the second through-hole 72 is omitted.

[0031] <Regarding the glass film> The portion of the glass film 50 that is not covered by both the first base electrode 61A and the second base electrode 62A is generally a uniform silicon dioxide glass layer. On the other hand, the portion of the glass film 50 that is covered by either the first base electrode 61A or the second base electrode 62A is a mixture of two types of glass layers with different compositions.

[0032] Specifically, as shown in FIG. 4, the glass film 50 has a base portion 51 and a specific portion 52. Most of the base portion 51 and the specific portion 52 are located between the first base electrode 61A and the outer surface 21 of the element body 20, and between the second base electrode 62A and the outer surface 21 of the element body 20 in the glass film 50. The base portion 51 contains oxides of one or more metal elements among alkali metals and alkaline earth metals in addition to silicon oxide. In this embodiment, the metal element is barium. In this embodiment, the base portion 51 contains oxides of barium and calcium among alkaline earth metals. Also, the base portion 51 contains zinc oxide. Further, the base portion 51 contains aluminum oxide.

[0033] The specific part 52 has a flat, layered shape when viewed in cross section. The specific part 52 contains an oxide of the same metal element as the base part 51 in addition to silicon oxide. That is, in the present embodiment, the specific part 52 contains an oxide of barium among alkaline earth metals. On the other hand, the specific part 52 does not contain an oxide of calcium. Further, the specific part 52 contains zinc oxide. On the other hand, the specific part 52 does not contain an oxide of aluminum.

[0034] And the content ratio of barium, which is the metal element in the specific part 52, is smaller than the content ratio of barium, which is the metal element in the base part 51. Further, the content ratio of silicon in the specific part 52 is larger than the content ratio of silicon in the base part 51. Also, the content ratio of zinc in the specific part 52 is larger than the content ratio of zinc in the base part 51.

[0035] <Method for manufacturing an electronic component> Next, a method for manufacturing the electronic component 10 will be described. As shown in FIG. 5, the method for manufacturing the electronic component 10 includes a laminate preparation step S11, an R chamfering step S12, a solvent introduction step S13, a catalyst introduction step S14, a green body introduction step S15, a polymer introduction step S16, and a metal alkoxide introduction step S17. Further, the method for manufacturing the electronic component 10 further includes a film formation step S18, a drying step S19, a firing step S20, a conductor coating step S21, a curing step S22, and a plating step S23.

[0036] First, when forming the base body 20, in the laminate preparation step S11, a laminate that is the base body 20 without the boundary surface 23 and the corner surface 24 is prepared. That is, the laminate is in a state before chamfering and is in the shape of a rectangular parallelepiped having six planes 22. For example, first, a plurality of ceramic sheets that will become the base body 20 are prepared. The sheet is in the form of a thin plate. On the sheet, a conductive paste that will become the first internal electrode 41 is laminated. On the laminated paste, a ceramic sheet that will become the base body 20 is laminated. On the sheet, a conductive paste that will become the second internal electrode 42 is laminated. In this way, the ceramic sheet and the conductive paste are laminated. Then, an unfired laminate is formed by cutting to a predetermined size. Thereafter, the unfired laminate is fired at a high temperature to prepare the laminate.

[0037] Next, the R chamfering process step S12 is performed. In the R chamfering process step S12, the boundary surface 23 and the corner surface 24 are formed on the laminate prepared in the laminate preparation step S11. For example, by barrel polishing, the corners of the laminate are R chamfered, thereby forming the boundary surface 23 having a curved surface and the corner surface 24 having a curved surface. Thereby, the base body 20 is formed.

[0038] Next, the solvent charging step S13 is performed. As shown in FIG. 6, in the solvent charging step S13, 2-propanol is charged into the reaction vessel 81 as the solvent 82. Next, as shown in FIG. 5, the catalyst charging step S14 is performed. As shown in FIG. 7, in the catalyst charging step S14, first, the stirring of the solvent 82 in the reaction vessel 81 is started. Then, aqueous ammonia is charged into the reaction vessel 81 as the aqueous solution 83 containing the catalyst. The catalyst in this embodiment is a hydroxide ion and functions as a catalyst for promoting the hydrolysis of the metal alkoxide 85 described later.

[0039] Next, as shown in FIG. 5, the base body charging step S15 is performed. As shown in FIG. 8, in the base body charging step S15, a plurality of base bodies 20 previously formed in the R chamfering process step S12 as described above are charged into the reaction vessel 81.

[0040] Next, as shown in FIG. 5, a polymer input step S16 is performed. As shown in FIG. 9, in the polymer input step S16, polyvinylpyrrolidone is input as the polymer 84 into the reaction vessel 81. Thereby, the polymer 84 introduced into the reaction vessel 81 adsorbs to the outer surface 21 of the green body 20.

[0041] Next, as shown in FIG. 5, a metal alkoxide input step S17 is performed. As shown in FIG. 10, in the metal alkoxide input step S17, liquid tetraethyl orthosilicate is input as the metal alkoxide 85 into the reaction vessel 81. Note that tetraethyl orthosilicate may also be referred to as tetraethoxysilane. In the present embodiment, the amount of the metal alkoxide 85 input in the metal alkoxide input step S17 is calculated based on the area of the outer surface 21 of the green body 20 input in the green body input step S15. Specifically, it is calculated by multiplying the amount of the metal alkoxide 85 per one green body 20 required to form the pre-diffusion glass film 50A covering the outer surface 21 of the green body 20 by the number of the green bodies 20. The pre-diffusion glass film 50A is a film in a state before the diffusion of the metal element contained in the glass of the conductor paste occurs, as will be described later. That is, the pre-diffusion glass film 50A is in a state of not containing the metal element derived from the conductor paste.

[0042] Next, as shown in FIG. 5, a film formation step S18 is performed. As shown in FIG. 11, in the film formation step S18, the stirring of the solvent 82 started in the above-described solvent input step S13 is continued for a predetermined time after the metal alkoxide 85 is introduced into the reaction vessel 81 by the metal alkoxide input step S17. In the film formation step S18, the pre-diffusion glass film 50A is formed by a liquid phase reaction in the reaction vessel 81.

[0043] Next, as shown in FIG. 5, a drying step S19 is performed. In the drying step S19, after the stirring is continued for a predetermined time in the film formation step S18, the green body 20 is taken out from the reaction vessel 81 and dried. Thereby, the sol-like pre-diffusion glass film 50A is dried to become a gel-like pre-diffusion glass film 50A.

[0044] Next, the firing step S20 is performed. In the firing step S20, the green body 20 covered with the gel-like pre-diffusion glass film 50A is heated. As a result, water and the polymer 84 vaporize from the gel-like pre-diffusion glass film 50A. Consequently, the pre-diffusion glass film 50A made of silicon dioxide is formed.

[0045] Next, the conductor coating step S21 is performed. In the conductor coating step S21, the conductor paste is applied to two locations, namely, a portion including the part covering the first end face 22A of the green body 20 and a portion including the part covering the second end face 22B of the green body 20, on the surface of the pre-diffusion glass film 50A. Specifically, the conductor paste is applied so as to cover the entire first end face 22A and a part of the glass film 50 on the four side faces 22C. Also, the conductor paste is applied so as to cover the entire second end face 22B and a part of the pre-diffusion glass film 50A on the four side faces 22C. The conductor paste has copper powder, glass, and an organic medium. The copper powder of the conductor paste becomes the first base electrode 61A and the second base electrode 62A by the subsequent curing step S22. The glass of the conductor paste has an additive containing one or more metal elements among alkali metals and alkaline earth metals. More specifically, the metal element is barium. Further, as an additive, the conductor paste contains calcium, aluminum, and zinc.

[0046] Next, the curing step S22 is performed. Specifically, in the curing step S22, the green body 20 coated with the pre-diffusion glass film 50A and the conductor paste is heated. As a result, the organic medium in the conductor paste vaporizes. And the copper powder in the conductor paste integrates to become the first base electrode 61A and the second base electrode 62A. That is, the materials of the first base electrode 61A and the second base electrode 62A are copper. Note that the first base electrode 61A and the second base electrode 62A may contain impurities.

[0047] At the same time, the glass in the conductive paste melts and integrates with a part of the pre-diffusion glass film 50A. However, the pre-diffusion glass film 50A consists of only substantially silicon oxide at the start of the curing step S22. Therefore, the pre-diffusion glass film 50A has a high melting point. Thus, a part of the pre-diffusion glass film 50A does not integrate with the glass of the conductive paste and remains. However, at this time, the metal elements contained in the additives of the glass in the conductive paste diffuse into the pre-diffusion glass film 50A made of silicon dioxide. As a result, metal elements penetrate into the pre-diffusion glass film 50A covering the outer surface 21 of the base body 20. After that, when the base body 20 is fired, the mixture of the glass derived from the conductive paste and the pre-diffusion glass film 50A becomes the base portion 51. On the other hand, the pre-diffusion glass film 50A that did not integrate with the glass of the conductive paste and remained becomes the specific portion 52. As described above, metal elements have also diffused into the pre-diffusion glass film 50A that did not integrate with the glass of the conductive paste and remained. Therefore, the specific portion 52 contains metal elements, although less than the base portion 51.

[0048] Note that in the portions of the pre-diffusion glass film 50A that are not covered by the conductive paste, the diffusion of metal elements as described above hardly occurs. Therefore, the portions of the pre-diffusion glass film 50A that are not covered by the conductive paste become a generally uniform glass layer without distinction such as the base portion 51 and the specific portion 52.

[0049] In this embodiment, during the heating in the curing step S22, due to the Kirkendall effect caused by the difference in the diffusion rates between the first internal electrode 41 and the first underlayer electrode 61A, silver and palladium contained on the first internal electrode 41 side are attracted to the first underlayer electrode 61A side which is made of copper. As a result, the first through-hole portion 71 extends through the glass film 50 from the first internal electrode 41 toward the first underlayer electrode 61A, and the first internal electrode 41 and the first underlayer electrode 61A are connected. This is the same for the second through-hole portion 72 that connects the second internal electrode 42 and the second underlayer electrode 62A.

[0050] Next, the plating process S23 is performed. In the plating process S23, electroplating is performed on the portions of the first base electrode 61A and the second base electrode 62A. As a result, a first metal layer 61B is formed on the surface of the first base electrode 61A. Also, a second metal layer 62B is formed on the surface of the second base electrode 62A. As shown in FIG. 4, the first metal layer 61B is electroplated with two types of nickel and tin, resulting in a two-layer structure of a nickel layer 61C and a tin layer 61D. Although not shown, similar to the first metal layer 61B, the second metal layer 62B is electroplated with two types of nickel and tin in order, resulting in a two-layer structure of a nickel layer and a tin layer. In this way, the electronic component 10 is formed.

[0051] (Operation of the Embodiment) When the electronic component 10 of the above embodiment is solder-mounted on a substrate or the like, it is surface-treated using a water-soluble flux. At this time, the water-soluble flux may penetrate from the interface between the first external electrode 61 and the glass film 50 into the interior of the glass film 50 and further into the element body 20.

[0052] (Effect of the Embodiment) (1) According to the above embodiment, the glass film 50 has a base portion 51 and a specific portion 52. And the specific portion 52 contains silicon oxide and an oxide of a metal element. And the content ratio of the metal element in the specific portion 52 is smaller than the content ratio of the metal element in the base portion 51. Therefore, an interface between the base portion 51 and the specific portion 52 can be present in the glass film 50. When an interface also exists in the glass film 50 in this way, even if the water-soluble flux penetrates into the glass film 50, the water-soluble flux extends on the interface. Therefore, it is difficult for the penetrated water-soluble flux to penetrate deeper than the interface between the base portion 51 and the specific portion 52. Thus, erosion from the outside to the element body 20 can be further prevented. In this way, according to the above embodiment, the flux resistance can be improved without necessarily adding silica powder.

[0053] (2) According to the above embodiment, the silicon content ratio of the specific part 52 is larger than the silicon content ratio of the base part 51. Thus, the composition of the specific part 52 is different from the composition of the base part 51. Therefore, the interface between the base part 51 and the specific part 52 becomes clearer.

[0054] (3) According to the above embodiment, the metal element is barium among the alkaline earth metals. Barium is relatively easy to obtain among the alkaline earth metals. Therefore, it is not necessary to prepare elements that are difficult to obtain.

[0055] (4) According to the above embodiment, the specific part 52 contains zinc oxide. Therefore, by containing zinc, it is likely to have a stable composition containing barium of the alkaline earth metal. (5) According to the above embodiment, the zinc content ratio of the specific part 52 is larger than the zinc content ratio of the base part 51. Therefore, the composition of the specific part 52 is different from the composition of the base part 51. Therefore, the interface between the base part 51 and the specific part 52 becomes clearer.

[0056] (6) According to the above embodiment, the first external electrode 61 has the first metal layer 61B. Therefore, the electronic component 10 is likely to be used by being mounted on a substrate or the like with solder. In other words, the electronic component 10 is likely to be exposed to a water-soluble flux. Therefore, the significance of the effect of preventing the intrusion of the water-soluble flux is great.

[0057] (7) According to the above embodiment, the first metal layer 61B spreads over a wider range than the first underlying electrode 61A. Therefore, a part of the first metal layer 61B is also located on the surface of the glass film 50. Therefore, when the outer edge of the first metal layer 61B is located outside the outer edge of the first underlying electrode 61A, it is possible to prevent a gap from occurring between the first external electrode 61 and the glass film 50. By preventing such a gap from occurring, it becomes easier to prevent the intrusion of the water-soluble flux between the first external electrode 61 and the glass film 50.

[0058] (Other Embodiments) The above embodiments can be implemented with the following modifications. The above embodiments and the following modification examples can be implemented in combination within a technically non - conflicting range.

[0059] · In the above embodiment, the electronic component 10 is not limited to a negative - characteristic thermistor component. For example, if there is any wiring inside the element body 20, it may be a thermistor component other than a negative - characteristic one, or it may be a multilayer capacitor component or an inductor component.

[0060] · The material of the element body 20 is not limited to the example of the above embodiment. The material of the element body 20 may be a composite body of resin and metal powder. · The shape of the element body 20 is not limited to the example of the above embodiment. For example, the element body 20 may be a polygonal column other than a quadrangular column having a central axis CA. Also, the element body 20 may be the core of a wound - type inductor component. For example, the core may have a so - called drum - core shape. Specifically, the core may have a columnar winding core part and flange parts provided at each end of the winding core part.

[0061] · The outer surface 21 of the element body 20 may not have the boundary surface 23 and the corner surface 24. For example, when the boundary between adjacent flat surfaces 22 of the outer surface 21 of the element body 20 is not chamfered, there is no curved surface at that boundary. Therefore, in such a case, the boundary surface 23 and the corner surface 24 may not exist.

[0062] · In the above embodiment, the shapes of the first internal electrode 41 and the second internal electrode 42 may be any shape as long as electrical conduction with the corresponding first external electrode 61 and second external electrode 62 can be ensured. Also, the number of the first internal electrode 41 and the second internal electrode 42 is not limited, and the number of internal electrodes may be one or three or more.

[0063] · The configuration of the first external electrode 61 is not limited to the example of the above embodiment. For example, the first external electrode 61 may be composed of only the first base electrode 61A, or the first metal layer 61B may not have a two-layer structure. This also applies to the second external electrode 62 in this regard.

[0064] · In the above embodiment, the combination of the materials of the first internal electrode 41 and the first base electrode 61A is not limited to the combination where one is copper and the other is a combination of silver and palladium. For example, it may be a combination of palladium and silver, copper and nickel, copper and silver, copper and palladium, silver and gold, nickel and cobalt, or nickel and gold. Also, for example, one may be copper and the other may be a combination of copper and nickel. Also, for example, one may be nickel and the other may be a combination of copper and nickel. Also, for example, one may be gold and the other may be a combination of silver and palladium.

[0065] · Note that depending on the combination of the first internal electrode 41 and the first base electrode 61A, the kirkendall effect may not be obtained. In this case, before the external electrode formation process, the first internal electrode 41 may be processed so as to be exposed. For example, the first end face 22A side of the blank 20 may be polished to physically remove a part of the glass film 50. Then, by performing the base electrode formation process, the first internal electrode 41 and the first base electrode 61A can be connected. Also, for example, after forming the first base electrode 61A, a glass film 50 may be formed including the surface of the first base electrode 61A, and the glass film 50 covering the surface of the first base electrode 61A may be removed. This also applies to the combination of the materials of the second internal electrode 42 and the second base electrode 62A in this regard.

[0066] · The location where the first external electrode 61 is disposed is not limited to the example of the above embodiment. For example, the first external electrode 61 may be disposed only on the first end face 22A and one side face 22C. This also applies to the second external electrode 62 in this regard.

[0067] <Regarding the glass film> · The glass film 50 does not necessarily cover all regions of the outer surface 21 of the base body 20. The range covered by the glass film 50 may be appropriately changed according to the shape of the base body 20, the positions of the first external electrode 61 and the second external electrode 62, etc.

[0068] · The metal element contained in the glass film 50 may be an alkali metal. Also, the metal element contained in the glass film 50 may be any one of lithium, sodium, and potassium among the alkali metals. Note that lithium, sodium, and potassium are relatively easy to obtain among the alkali metals. Therefore, there is no need to prepare elements that are difficult to obtain.

[0069] · The metal element contained in the glass film 50 may be calcium among the alkaline earth metals. Also, the metal contained in the glass film 50 may be other metals among the alkaline earth metals.

[0070] · The specific part 52 may contain aluminum oxide. The specific part 52 may contain zinc oxide. Also, the base part 51 and the specific part 52 may contain additives of other elements. Depending on the content ratio of other elements, the silicon content ratio of the specific part 52 may be equal to or less than the silicon content ratio of the base part 51.

[0071] · The base part 51 does not necessarily contain aluminum oxide. The base part 51 does not necessarily contain zinc oxide. Furthermore, the zinc content ratio of the specific part 52 may be equal to or less than the zinc content ratio of the base part 51.

[0072] · The material of the glass film 50 is not limited to the examples of the above embodiments. For example, the glass is not limited to silicon dioxide only, and may be a multi-component oxide containing Si, such as B-Si-based, Si-Zn-based, Zr-Si-based, or Al-Si-based oxides. Further, the glass may be a multi-component oxide containing an alkali metal and Si, such as Al-Si-based, Na-Si-based, K-Si-based, or Li-Si-based oxides. Moreover, the glass may be a multi-component oxide containing an alkaline earth metal and Si, such as Mg-Si-based, Ca-Si-based, Ba-Si-based, or Sr-Si-based. And the glass may not contain Si and may be a mixture of these. When the material of the glass film 50 contains boron, the specific part 52 may contain boron oxide. Also, in this case, the base part 51 may contain boron oxide.

[0073] · Further, the material of the glass film 50 may contain, in addition to the glass, surface treatment agents or antistatic agents such as pigments, silicone-based flame retardants, silane coupling agents, and titanate coupling agents.

[0074] More specifically, the glass film 50 may contain, in addition to the glass, additives such as organic acid salts, oxides, inorganic salts, organic salts, fine particles of other metal oxides, and nanoparticles. Examples of the organic acid salts include salts of oxo acids such as soda ash, sodium carbonate, sodium hydrogen carbonate, sodium percarbonate, sodium sulfite, sodium hydrogen sulfite, sodium sulfate, sodium thiosulfate, sodium nitrate, and sodium sulfite, and halogen compounds such as sodium fluoride, sodium chloride, sodium bromide, and sodium iodide.

[0075] Examples of the oxides include sodium peroxide, and examples of the hydroxides include sodium hydroxide. Examples of the inorganic salts include sodium hydride, sodium sulfide, sodium hydrogen sulfide, sodium silicate, trisodium phosphate, sodium borate, sodium borohydride, sodium cyanide, sodium cyanate, and sodium tetrachloroaurate.

[0076] Examples of the inorganic salts include calcium peroxide, calcium hydroxide, calcium fluoride, calcium chloride, calcium bromide, calcium iodide, calcium hydride, calcium carbide, and calcium phosphide.

[0077] In addition, examples of the additives may include oxoacid salts such as calcium carbonate, calcium hydrogen carbonate, calcium nitrate, calcium sulfate, calcium sulfite, calcium silicate, calcium phosphate, calcium pyrophosphate, calcium hypochlorite, calcium chlorate, calcium perchlorate, calcium bromate, calcium iodate, calcium arsenite, calcium chromate, calcium tungstate, calcium molybdate, calcium carbonate magnesium, hydroxyapatite. Further, examples of the additives include calcium acetate, calcium gluconate, calcium citrate, calcium malate, calcium lactate, calcium benzoate, calcium stearate, and calcium aspartate.

[0078] Also, for example, the additives may be lithium carbonate, lithium chloride, lithium titanate, lithium nitride, lithium peroxide, lithium citrate, lithium fluoride, lithium hexafluorophosphate, lithium acetate, lithium iodide, lithium hypochlorite, lithium tetraborate, lithium bromide, lithium nitrate, lithium hydroxide, lithium aluminum hydride, lithium triethylborohydride, lithium hydride, lithium amide, lithium imide, lithium diisopropylamide, lithium tetramethylpiperidide, lithium sulfide, lithium sulfate, lithium thiophenolate, and lithium phenoxide.

[0079] Also, for example, the additives may be boron triiodide, sodium cyanoborohydride, sodium borohydride, tetrafluoroboric acid, triethylborane, borax, and boric acid.

[0080] For example, the additive may also be potassium arsenide, potassium bromide, potassium carbide, potassium chloride, potassium fluoride, potassium hydride, potassium iodide, potassium triiodide, potassium azide, potassium nitride, potassium superoxide, potassium ozonide, potassium peroxide, potassium phosphide, potassium sulfide, potassium selenide, potassium telluride, potassium tetrafluoroaluminate, potassium tetrafluoroborate, potassium tetrahydroborate, potassium methanide, potassium cyanide, potassium formate, potassium hydrogen fluoride, potassium tetraiodomercurate(II), potassium hydrogen sulfide, potassium octachlorodimolybdate(II), potassium amide, potassium hydroxide, potassium hexafluorophosphate, potassium carbonate, potassium tetrachloroplatinate(II), potassium hexachloroplatinate(IV), potassium nonahydridorhenate(VII), potassium sulfate, potassium acetate, potassium dicyanoaurate(I), potassium hexanitrocobaltate(III), potassium hexacyanoferrate(III), potassium hexacyanoferrate(II), potassium methoxide, potassium ethoxide, potassium tert-butoxide, potassium cyanate, potassium fulminate, potassium thiocyanate, potassium alum, potassium aluminate, potassium arsenite, potassium bromate, potassium hypochlorite, potassium chlorite, potassium chlorate, potassium perchlorate, potassium carbonate, potassium chromate, potassium dichromate, potassium tetrakis(peroxo)chromate(V), potassium cuprate(III), potassium ferrate, potassium iodate, potassium periodate, potassium permanganate, potassium manganate, potassium hypomanganate, potassium molybdate, potassium nitrite, potassium nitrate, tripotassium phosphate, potassium perrhenate, potassium selenate, potassium silicate, potassium sulfite, potassium sulfate, potassium thiosulfate, potassium dithionite, potassium dithionate, potassium disulfate, potassium peroxodisulfate, potassium dihydrogen arsenite, potassium hydrogen arsenite, potassium hydrogen carbonate, potassium dihydrogen phosphate, potassium hydrogen phosphate, potassium hydrogen selenate, potassium hydrogen sulfite, potassium hydrogen sulfate, potassium peroxomonosulfate.

[0081] For example, the additive may be barium sulfite, barium chloride, barium chlorate, barium perchlorate, barium peroxide, barium chromate, barium acetate, barium cyanide, barium bromide, barium oxalate, barium nitrate, barium hydroxide, barium hydride, barium carbonate, barium iodide, barium sulfide, or barium sulfate. Alternatively, the additive may be sodium acetate or sodium citrate.

[0082] The additive may also be fine particles or nanoparticles of a metal oxide. For example, examples of the metal oxide include sodium oxide, calcium oxide, lithium oxide, boron oxide, potassium oxide, barium oxide, silicon oxide, titanium oxide, zirconium oxide, aluminum oxide, zinc oxide, and magnesium oxide.

[0083] · The specific part 52 is not limited to one layer. The number of specific parts 52 may be plural. Further, the shape of the specific part 52 does not have to be layer-like. For example, in the modified example shown in FIG. 12, the glass film 50 has a plurality of specific parts 52. When viewed in cross-section in a plane orthogonal to the outer surface 21 of the base body 20, the major axis of the specific part 52 is three times or more the minor axis. The major axis is the maximum length of the line segments that can be drawn from outer edge to outer edge passing through the geometric center of one specific part 52 when viewed in cross-section. The minor axis is the length of the line segment that can be drawn from outer edge to outer edge passing through the geometric center of the same specific part 52 and orthogonal to the major axis when viewed in cross-section. That is, according to the modified example shown in FIG. 12, the number of interfaces between the base part 51 and the specific part 52 is increased by the plurality of specific parts 52. The major axis of one specific part 52 is three times or more the minor axis, that is, plate-like or needle-like in cross-sectional view. Therefore, the passage through the base part 51 from the outside of the glass film 50 to the base body 20 can be complicated. Also, the possibility of arranging more interfaces in the direction orthogonal to the outer surface 21 of the base body 20 can be increased.

[0084] · In the method for manufacturing the electronic component 10, the metal alkoxide 85 may be, for example, sodium methoxide, sodium ethoxide, calcium diethoxide, lithium isopropoxide, lithium ethoxide, lithium tert-butoxide, lithium methoxide, boron alkoxide, potassium t-butoxide, tetraethyl orthosilicate, allyltrimethoxysilane, isobutyl(trimethoxy)silane, tetrapropyl orthosilicate, tetramethyl orthosilicate, [3-(diethylamino)propyl]trimethoxysilane, triethoxy(octyl)silane, triethoxyvinylsilane, triethoxyphenylsilane, trimethoxyphenylsilane, trimethoxymethylsilane, butyltrichlorosilane, n-propyltriethoxysilane, methyltrichlorosilane, dimethoxy(methyl)octylsilane, dimethoxydimethylsilane, tris(tert-butoxy)silanol, tris(tert-pentoxy)silanol, hexadecyltrimethoxysilane, dipotassium tris(1,2-benzenediolato-O,O’)silicate, tetrabutyl orthosilicate, aluminum silicate, calcium silicate, tetramethylammonium silicate solution, chlorotriisopropoxytitanium(IV), titanium(IV) isopropoxide, titanium(IV) 2-ethylhexyloxide, titanium(IV) ethoxide, titanium(IV) butoxide, titanium(IV) tert-butoxide, titanium(IV) propoxide, titanium(IV) methoxide, zirconium(IV) bis(diethyl citrate) dipropoxide, zirconium(IV) dibutoxide(bis-2,4-pentanedionate), zirconium(IV) 2-ethylhexanoate, zirconium(IV) isopropoxide isopropanol complex, zirconium(IV) ethoxide, zirconium(IV) butoxide, zirconium(IV) tert-butoxide, zirconium(IV) propoxide, aluminum tert-butoxide, aluminum isopropoxide, aluminum ethoxide, aluminum-tri-sec-butoxide, aluminum phenoxide.

[0085] · In the method for manufacturing the electronic component 10, instead of the metal alkoxide 85, a metal complex or acetate, which is a precursor of the metal alkoxide 85, may be used. In this case, in the metal alkoxide input step S17, a metal complex or acetate, which is a metal alkoxide precursor, may be input. Examples of the metal complex include acetylacetonates such as lithium acetylacetonate, titanium(IV) oxyacetylacetonate, titanium diisopropoxide bis(acetylacetonate), zirconium(IV) trifluoroacetylacetonate, zirconium(IV) acetylacetonate, aluminum acetylacetonate, aluminum(III) acetylacetonate, calcium(II) acetylacetonate, and zinc(II) acetylacetonate. Further, for example, examples of the acetate include zirconium acetate, zirconium(IV) hydroxide acetate, and basic aluminum acetate.

[0086] · The method for manufacturing the electronic component 10 is not limited to the examples of the above embodiment. For example, the solvent input step S13 may be performed after the catalyst input step S14 and the base body input step S15. Further, the solvent 82 is not limited to 2-propanol. The solvent 82 may be appropriately changed as long as it can sufficiently disperse the metal alkoxide 85.

[0087] · The technical idea derivable from the above embodiment and the modification examples is described below. <1> A base body, A glass film covering the outer surface of the base body, An external electrode laminated on the outer surface of the glass film and having at least a base electrode, The glass film has a base portion containing an oxide of at least one metal element among alkali metals and alkaline earth metals in addition to silicon oxide, and a specific portion containing an oxide of the same metal element as the base portion in addition to silicon oxide, The content ratio of the metal element in the specific portion is smaller than the content ratio of the metal element in the base portion An electronic component.

[0088] <2> The silicon content ratio of the specific part is greater than the silicon content ratio of the base part. The electronic component according to <1>.

[0089] <3> The metal element is any one of lithium, sodium, and potassium among the alkali metals. The electronic component according to <1> or <2>.

[0090] <4> The metal element is any one of calcium and barium among the alkaline earth metals. The electronic component according to <1> or <2>.

[0091] <5> The specific part contains an oxide of any one of the elements zinc, boron, and aluminum. The electronic component according to any one of <1> to <4>.

[0092] <6> The base part contains zinc oxide, The specific part contains zinc oxide, The zinc content ratio of the specific part is greater than the zinc content ratio of the base part. The electronic component according to <5>.

[0093] <7> The glass film has a plurality of the specific parts, When viewed in cross-section, the major axis is the maximum length among the lengths of the line segments that pass through the geometric center of the specific part and can be drawn from outer edge to outer edge, When viewed in cross-section, when the minor axis is the length of the line segment that passes through the geometric center of the specific part, is orthogonal to the major axis, and can be drawn from outer edge to outer edge, The major axis is 3 times or more the minor axis. The electronic component according to any one of <1> to <6>.

[0094] <8> The external electrode further has a metal layer, The metal layer is provided on the surface of the base electrode The electronic component according to any one of <1> to <7>.

[0095] <9> A part of the metal layer is located on the surface of the glass film The electronic component according to <8>.

Explanation of reference numerals

[0096] 10... Electronic component 20... Element body 21... Outer surface 50... Glass film 51... Base part 52... Specific part 61... First external electrode 61A... First base electrode 61B... First metal layer

Claims

1. A base body, a glass film covering the outer surface of the base body, and an external electrode laminated on the outer surface of the glass film and having at least a base electrode, wherein the glass film has a base portion containing an oxide of one or more metal elements among alkali metals and alkaline earth metals in addition to silicon oxide, and a specific portion containing an oxide of the same metal element as the base portion in addition to silicon oxide, and the content ratio of the metal element in the specific portion is smaller than the content ratio of the metal element in the base portion an electronic component.

2. The content ratio of silicon in the specific portion is larger than the content ratio of silicon in the base portion The electronic component according to claim 1.

3. The metal element is any one of lithium, sodium, and potassium among alkali metals The electronic component according to claim 1.

4. The metal element is any one of calcium and barium among alkaline earth metals The electronic component according to claim 1.

5. The specific portion contains an oxide of any one of the elements zinc, boron, and aluminum The electronic component according to claim 1.

6. The base portion contains zinc oxide, the specific portion contains zinc oxide, and the content ratio of zinc in the specific portion is larger than the content ratio of zinc in the base portion The electronic component according to claim 5.

7. The glass film has a plurality of the specific portions, when viewed in cross section, with the maximum length of the line segments that can be drawn from outer edge to outer edge passing through the geometric center of the specific portion as the major axis, when viewed in cross section, with the length of the line segment that can be drawn from outer edge to outer edge passing through the geometric center of the specific portion and orthogonal to the major axis as the minor axis, the major axis is 3 times or more the minor axis The electronic component according to claim 1.

8. The external electrode further has a metal layer, and the metal layer is provided on the surface of the base electrode The electronic component according to claim 1.

9. A part of the metal layer is located on the surface of the glass film The electronic component according to claim 8.

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