Electronic Components

Abstract

An element (20) has a recess (26A) that is recessed from an outer surface (21). The inner surface of the recess (26A) is not covered with a glass film (50). When the recess (26A) is viewed facing in a direction orthogonal to the outer surface (21), at least a portion of an outer edge of the recess (26A) is curved. When the recess (26A) is viewed in a cross section orthogonal to the outer surface (21), at least a portion of the inner surface of the recess (26A) is curved.

Description

[Technical field]

[0001] The present invention relates to electronic components. [Background technology]

[0002] The electronic component described in Patent Document 1 includes an element body and a glass film that covers the outer surface of the element body. The glass film covers the outer surface of the element body without leaving any gaps. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-311676 A Summary of the Invention [Problem to be solved by the invention]

[0004] The electronic component described in Patent Document 1 may be subjected to an external impact. When an external impact is applied to an electronic component, the load from the impact may be concentrated at a specific location on the surface of the element body. If a large force is concentrated at a specific location, a crack may occur on the surface of the element body at that specific location. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides an electronic component comprising an element body, wiring located inside the element body, and a glass film covering an outer surface of the element body, wherein the element body has a depression recessed from the outer surface, an inner surface of the depression is not covered by the glass film, and when the depression is viewed in a direction perpendicular to the outer surface, at least a portion of an outer edge of the depression is curved, and when the depression is viewed in a cross section perpendicular to the outer surface, at least a portion of the inner surface of the depression is curved.

[0006] According to the above configuration, even if an impact acts on the surface of the element body, the impact is divided by the recess. Therefore, the impact is prevented from being concentrated on a specific location on the surface of the element body. Furthermore, since at least a part of the outer edge and at least a part of the inner surface of the recess are curved, the direction of the impact is likely to be dispersed in this curved portion. Furthermore, since the inner surface of the recess is not covered with a glass film, it is also possible to prevent an external impact from acting on a specific location on the inner surface of the recess through the glass film. Effect of the Invention

[0007] This makes it possible to prevent impacts from being concentrated on specific points on the surface of the element body. [Brief description of the drawings]

[0008] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] Cross-sectional view taken along line 3-3 in Figure 2. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] 5A to 5C are explanatory diagrams illustrating a manufacturing method of an electronic component. [Figure 8] 5A to 5C are explanatory diagrams illustrating a manufacturing method of an electronic component. [Figure 9] 5A to 5C are explanatory diagrams illustrating a manufacturing method of an electronic component. [Figure 10] 5A to 5C are explanatory diagrams illustrating a manufacturing method of an electronic component. [Figure 11] 5A to 5C are explanatory diagrams illustrating a manufacturing method of an electronic component. [Figure 12] 5A to 5C are explanatory diagrams illustrating a manufacturing method of an electronic component. [Figure 13] 11 is a table showing the results of comparing electronic components of an embodiment and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <An embodiment of the electronic component> Hereinafter, an embodiment of an electronic component will be described with reference to the drawings. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from the actual ones or from those in other drawings. In addition, although hatching is applied in the cross-sectional views, hatching of some components may be omitted to facilitate understanding.

[0010] (Overall structure) 1, the electronic component 10 is, for example, a surface-mount type negative temperature coefficient thermistor component that is mounted on a circuit board, etc. Note that a negative temperature coefficient thermistor component has a characteristic that its resistance value decreases as the temperature increases.

[0011] The electronic component 10 includes an element body 20. The element body 20 is generally rectangular prism-shaped and has a central axis CA. In the following description, an axis extending along the central axis CA is defined as a first axis X. One of the axes perpendicular to the first axis X is defined as a second axis Y. An axis perpendicular to the first axis X and the second axis Y is defined as a third axis Z. One of the directions along the first axis X is defined as a first positive direction X1, and the direction along the first axis X opposite to the first positive direction X1 is defined as a first negative direction X2. One of the directions along the second axis Y is defined as a second positive direction Y1, and the direction along the second axis Y opposite to the second positive direction Y1 is defined as a second negative direction Y2. One of the directions along the third axis Z is defined as a third positive direction Z1, and the direction along the third axis Z opposite to the third positive direction Z1 is defined as a third negative direction Z2.

[0012] The outer surface 21 of the element body 20 has six planar planes 22. The "surface" of the element body 20 here refers to a surface that can be observed when the entire element body 20 is observed. In other words, even if there are minute irregularities or steps that cannot be seen unless a part of the element body 20 is magnified and observed with a microscope, the surface is expressed as a flat surface or a curved surface. The six planes 22 extend in different directions. The six planes 22 are roughly divided 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. The four side faces 22C are 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, respectively.

[0013] The outer surface 21 of the element body 20 has twelve boundary surfaces 23. The boundary surfaces 23 include curved surfaces that exist at the boundaries between adjacent flat surfaces 22. That is, the boundary surfaces 23 include curved surfaces that are formed, for example, by R-chamfering the corners that form the adjacent flat surfaces 22.

[0014] Furthermore, the outer surface 21 of the element body 20 has eight spherical corner surfaces 24. The corner surfaces 24 are boundary portions between three adjacent flat surfaces 22. In other words, the corner surfaces 24 include curved surfaces at the intersections of the three boundary surfaces 23. That is, the corner surfaces 24 include curved surfaces formed, for example, by R-chamfering the corners formed by the three adjacent flat surfaces 22.

[0015] 1 and 2, the surface of a glass film 50, which will be described later, is regarded as being the same as the outer surface 21 of the element body 20 and is given a reference symbol. As shown in Fig. 2, the element body 20 has a larger dimension along the first axis X than along the third axis Z. Also, as shown in Fig. 1, the element body 20 has a larger dimension along the first axis X than along the second axis Y. Also, the material of the element body 20 is a semiconductor. Specifically, the material of the element body 20 is a ceramic obtained by firing a metal oxide containing at least one of Mn, Fe, Ni, Co, Ti, Ba, Al, and Zn.

[0016] 3, the electronic component 10 includes, as wiring, 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 element body 20.

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

[0018] The first internal electrode 41 has a rectangular plate shape. The main surface of the first internal electrode 41 is perpendicular to the second axis Y. The second internal electrode 42 has the same rectangular plate shape as the first internal electrode 41. The main surface of the second internal electrode 42 is perpendicular 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 element 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 element 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] 3, the first internal electrodes 41 and the second internal electrodes 42 are positioned alternately in the direction along the second axis Y. That is, 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 from the side surface 22C facing the second positive direction Y1 to the second negative direction Y2. In this embodiment, the distances between the internal electrodes in the direction along the second axis Y are equal.

[0021] As shown in Fig. 1, the two first internal electrodes 41 and the two second internal electrodes 42 are both located at the center of the element body 20 in the direction along the third axis Z. On the other hand, as shown in Fig. 3, the first internal electrodes 41 are located closer to the first positive direction X1, and the second internal electrodes 42 are located 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 element 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 element body 20 and does not reach the end of the element 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 element 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 element body 20 and does not reach the end of the element 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 element body 20. In this embodiment, the glass film 50 covers the entire area of ​​the outer surface 21 of the element body 20. The material of the glass film 50 is glass. In this embodiment, the glass is made of silicon dioxide.

[0024] 3, the electronic component 10 includes a first external electrode 61 and a second external electrode 62. The first external electrode 61 includes 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 portion of the outer surface 21 of the element 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 element body 20 and portions of the four side faces 22C in the first positive direction X1. In this embodiment, the first base electrode 61A is made of silver and glass.

[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. Although not shown, the first metal layer 61B has a two-layer structure of a nickel layer and a tin layer in this order from the first base electrode 61A side. The thickness of the nickel layer is preferably 0.5 μm or more and 10 μm or less.

[0026] 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 in a portion 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 portions of the four side faces 22C on the first negative direction X2 side. In this embodiment, the material of the second base electrode 62A is the same as the material of the first external electrode 61, that is, silver and glass.

[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. Although not shown, the second metal layer 62B has a two-layer structure of a nickel layer and a tin layer in this order from the second base electrode 62A side, similar to the first metal layer 61B. The thickness of the nickel layer is preferably 0.5 μm or more and 10 μm or less.

[0028] The second external electrode 62 does not reach the first external electrode 61 on the side surface 22C, and is disposed apart from the first external electrode 61 in the direction along the first axis X. In addition, in the central portion of the side surface 22C of the element body 20 in the direction along the first axis X, the first external electrode 61 and the second external electrode 62 are not laminated, and the glass film 50 is exposed. Note that in Figs. 1 and 3, the first external electrode 61 and the second external electrode 62 are illustrated by two-dot chain lines.

[0029] 3, the first external electrode 61 and the end of the first internal electrode 41 on the first positive direction X1 side are connected to each other via a first penetration portion 71 that penetrates the glass film 50. Therefore, the first external electrode 61 is electrically connected to the first internal electrode 41. Note that, as will be described in detail later, the first penetration portion 71 is formed during the manufacturing process of the electronic component 10 by the palladium that constitutes the first internal electrode 41 extending toward the first external electrode 61 side.

[0030] The second external electrode 62 and the end of the second internal electrode 42 on the first negative direction X2 side are connected via a second penetration portion 72 penetrating the glass film 50. Therefore, the second external electrode 62 is electrically connected to the second internal electrode 42. The second penetration portion 72 is also formed by the palladium constituting the first internal electrode 41 extending toward the second external electrode 62 side in the manufacturing process of the electronic component 10, similar to the first penetration portion 71. Note that in FIG. 3, the first internal electrode 41 and the first penetration portion 71 are illustrated as separate members with a boundary, but in reality, there is no clear boundary between them. The same applies to the second penetration portion 72. Also, the first penetration portion 71 is not illustrated in FIG. 1.

[0031] (Regarding the through holes in the glass film and the depressions in the element) 3, the glass film 50 has a plurality of through holes 51. The plurality of through holes 51 penetrate the glass film 50. The plurality of through holes 51 are present in portions of the glass film 50 that are not covered by the first external electrode 61 and the second external electrode 62.

[0032] The element body 20 has a plurality of recesses 26. The plurality of recesses 26 are recessed from the outer surface 21 of the element body 20. The recesses 26 are connected to the inside of the through holes 51. Therefore, when the electronic component 10 is viewed in a direction perpendicular to the outer surface 21, the recesses 26 overlap with the through holes 51. The plurality of recesses 26 include a recess 26A and a recess 26B, which will be described later.

[0033] 4, when the recess 26A is viewed in a direction perpendicular to the outer surface 21 of the element body 20, the outer edge of the recess 26A is all curved. Specifically, when the recess 26A is viewed in a direction perpendicular to the outer surface 21 of the element body 20, the outer edge of the recess 26A is substantially circular. The outer edge of the recess 26A coincides with the opening of the through-hole 51.

[0034] 5, when the recess 26A is viewed in a cross section perpendicular to the outer surface 21, a part of the inner surface of the recess 26A is curved. Moreover, the inner surface of the recess 26A is not covered with the glass film 50. Furthermore, no other members are present in the internal space of the recess 26A, and it is an empty space.

[0035] When the depression 26A is viewed in a direction perpendicular to the outer surface 21, the area of ​​the region surrounded by the outer edge of the depression 26 is defined as the opening area of ​​the depression 26A. In this case, the opening area of ​​each depression 26A is 1 μm 2 More than 2000μm 2 The calculation of the opening area of ​​depression 26A is as follows. First, depression 26A is photographed with an electron microscope in a direction perpendicular to outer surface 21. Next, the photographed image is binarized based on differences in brightness, saturation, or color to identify the outer edge of depression 26A. Then, by performing image processing, the area of ​​the region surrounded by the identified outer edge of depression 26A is calculated as the opening area of ​​depression 26A.

[0036] Furthermore, the point that passes through the geometric center of the outer edge of the depression 26A and where the distance from the outer edge to the outer edge of the depression 26A is the longest is defined as the opening diameter D. As described above, the outer edge of the depression 26A is substantially circular. For this reason, a virtual circle that is most similar to the depression 26A may be drawn, and the center of the virtual circle may be regarded as the geometric center, and the diameter of the virtual circle may be regarded as the longest distance from the outer edge to the outer edge. In this case, in a cross section that is perpendicular to the outer surface 21 and includes the opening diameter D, the maximum depth H of the depression 26A with respect to the opening diameter D is 25% or more and 50% or less. More specifically, the maximum depth H of the depression 26A with respect to the opening diameter D is 30%. The maximum depth H of the depression 26A is the longest distance from a virtual line connecting the outer edges of the depression 26A to the inner surface of the depression 26A in a direction perpendicular to the virtual line when the depression 26A is viewed in a cross section perpendicular to the outer surface 21.

[0037] The volume of the inner space of the recess 26A is defined as the recess volume. 3 More than 20000μm 3The volume of the depression is calculated by assuming that the internal space of the depression 26A is a spherical notch. First, the opening diameter D and maximum depth H of the depression 26A are measured. Next, the volume of the spherical notch is calculated as the depression volume from these values.

[0038] 4, grain boundaries of multiple ceramic particles in the element body 20 are present on the inner surface of the recess 26A. Furthermore, when the electronic component 10 is viewed in a direction perpendicular to the outer surface 21 of the element body 20, the first internal electrode 41 and the second internal electrode 42 are not present on the inner surface of the recess 26A. In other words, the recess 26A is not recessed to the extent that the first internal electrode 41 and the second internal electrode 42 are exposed.

[0039] 6, when the recess 26B is viewed in a cross section perpendicular to the outer surface 21, a part of the inner surface of the recess 26B is curved.

[0040] The electronic component 10 includes a filler 63. The material of the filler 63 is tin. The filler 63 is located in the inner space of the recess 26B. The filler 63 covers the entire inner surface of the recess 26B. A part of the filler 63 protrudes from the recess 26B and reaches the outside of the outer edge of the recess 26B. That is, when the electronic component 10 is viewed in a direction perpendicular to the outer surface 21, the filler 63 covers a wider area than the recess 26B. Therefore, when the electronic component 10 is viewed in a direction perpendicular to the outer surface 21, the outer edge of the filler 63 covers the vicinity of the recess 26B in the glass film 50. The opening area, opening diameter D, maximum depth H, and recess volume of the recess 26B are the same as those of the recess 26A.

[0041] The ratio of the total value of the opening area of ​​all the recesses 26, including the recesses 26A and the recesses 26B, to the area of ​​the outer surface 21 is defined as the area ratio. In this case, the area ratio is 0.1% or more and 60.0% or less. The area ratio is calculated as follows. First, an image including a measurement range on the side surface 22C of the outer surface 21 is acquired. The measurement range is a rectangular range on one side surface 22C having a first side extending in a direction along the first axis X and a second side extending in a direction perpendicular to the first axis X. The dimension of the first side is 0.4 times the dimension of the electronic component 10 in the direction along the first axis X. The first side is not in contact with the first external electrode 61 and the second external electrode 62. The dimension of the second side is 0.75 times the dimension of the side surface 22C in the direction perpendicular to the first axis X. Next, the image including the measurement range is binarized to distinguish whether it is a recess 26 or not. Next, the total value of the opening areas of all the dents 26 in the measurement range is calculated by image processing, and then the area ratio, which is the ratio of the total value of the opening areas of all the dents 26 in the measurement range to the area of ​​the measurement range, is calculated.

[0042] (About the manufacturing process of electronic components) Next, a method for manufacturing the electronic component 10 will be described. 7, the method for manufacturing electronic component 10 includes a laminate preparation step S11, a R-chamfering step S12, a solvent introduction step S13, a catalyst introduction step S14, an element introduction step S15, a polymer introduction step S16, and a metal alkoxide introduction step S17. The method for manufacturing electronic component 10 also includes a film formation step S18, a water immersion step S19, a drying step S20, a conductor application step S21, a curing step S22, and a plating step S23.

[0043] First, in forming the element body 20, in the laminate preparation step S11, a laminate is prepared as the element body 20 having no boundary surface 23 and no corner surface 24. That is, the laminate is in a state before R-chamfering, and has a rectangular parallelepiped shape having six planes 22. For example, first, a plurality of ceramic sheets that will become the element body 20 are prepared. The sheets are thin plate-like. A conductive paste that will become the first internal electrode 41 is laminated on the sheets. A ceramic sheet that will become the element body 20 is laminated on the laminated paste. A conductive paste that will become the second internal electrode 42 is laminated on the sheets. In this way, the ceramic sheet and the conductive paste are laminated. Then, the laminate is cut to a predetermined size to form an unfired laminate. After that, the unfired laminate is fired at a high temperature to prepare the laminate.

[0044] Next, a R-chamfering process S12 is performed. In the R-chamfering process S12, a boundary surface 23 and a corner surface 24 are formed on the laminate prepared in the laminate preparation process S11. For example, the corners of the laminate are R-chamfered by barrel polishing, thereby forming a boundary surface 23 having a curved surface and a corner surface 24 having a curved surface. In this way, an element body 20 is formed.

[0045] Next, a solvent introduction step S13 is performed. As shown in Fig. 8, in the solvent introduction step S13, 2-propanol is introduced into a reaction vessel 81 as a solvent 82. Next, a catalyst introduction step S14 is performed as shown in Fig. 7. As shown in Fig. 9, in the catalyst introduction step S14, first, stirring of the solvent 82 in the reaction vessel 81 is started. Then, ammonia water is introduced into the reaction vessel 81 as an aqueous solution 83 containing a catalyst. The catalyst in this embodiment is a hydroxide ion, and functions as a catalyst for promoting hydrolysis of a metal alkoxide 85 described later.

[0046] Next, an element body charging step S15 is performed as shown in Fig. 7. As shown in Fig. 10, in the element body charging step S15, a plurality of element bodies 20 formed in advance in the R chamfering step S12 as described above are charged into a reaction vessel 81.

[0047] Next, a polymer introduction step S16 is performed as shown in Fig. 7. As shown in Fig. 11, in the polymer introduction step S16, polyvinylpyrrolidone is introduced into a reaction vessel 81 as a polymer 84. As a result, the polymer 84 introduced into the reaction vessel 81 is adsorbed onto the outer surface 21 of the element body 20.

[0048] Next, as shown in Fig. 7, a metal alkoxide introduction step S17 is performed. As shown in Fig. 12, in the metal alkoxide introduction step S17, liquid tetraethyl orthosilicate is introduced into the reaction vessel 81 as the metal alkoxide 85. Note that tetraethyl orthosilicate is also called tetraethoxysilane. In this embodiment, the amount of metal alkoxide 85 introduced in the metal alkoxide introduction step S17 is calculated based on the area of ​​the outer surface 21 of the element body 20 introduced in the element introduction step S15. Specifically, the amount of metal alkoxide 85 required per element body 20 to form the glass film 50 covering the outer surface 21 of the element body 20 is multiplied by the number of element bodies 20 to calculate the amount.

[0049] 7, a film formation step S18 is performed. In the film formation step S18, the stirring of the solvent 82 started in the above-mentioned solvent introduction step S13 is continued for a predetermined time after the metal alkoxide 85 is introduced into the reaction vessel 81 in the metal alkoxide introduction step S17. In the film formation step S18, a glass film 50 containing a polymer 84 and moisture is formed by a liquid phase reaction in the reaction vessel 81.

[0050] Next, a water immersion step S19 is performed. In the water immersion step S19, after stirring is continued for a predetermined time in the film formation step S18, the element body 20 is removed from the reaction vessel 81 and immersed in water. As a result, a part of the polymer 84 adsorbed on the outer surface 21 of the element body 20 is dissolved in the water, and a part of the glass component of the glass film 50 falls off.

[0051] Next, the drying step S20 is performed. In the drying step S20, the element body 20 is taken out of the water and dried. As a result, the sol-like glass film 50 is dried and becomes a gel-like glass film 50.

[0052] Next, a conductor application step S21 is performed. In the conductor application step S21, a conductor paste is applied to two locations on the surface of the glass film 50: a portion including a portion covering the first end face 22A of the element body 20, and a portion including a portion covering the second end face 22B of the element body 20. Specifically, the conductor paste is applied so as to cover the glass film 50 over the entire first end face 22A and parts of the four side faces 22C. The conductor paste is also applied so as to cover the glass film 50 over the entire second end face 22B and parts of the four side faces 22C.

[0053] Next, a hardening step S22 is performed. Specifically, in the hardening step S22, the element body 20 to which the glass film 50 and the conductor paste are applied is heated. As a result, water and polymer 84 are vaporized from the gel-like glass film 50, and the glass film 50 covering the outer surface 21 of the element body 20 is baked and hardened as shown in FIG. 3. At this time, a through hole 51 penetrating the glass film 50 is formed due to the difference in the amount of thermal contraction at the boundary of the portion where the glass film 50 was partially dropped in the above-mentioned water immersion step S19. At the same time, the conductor paste applied in the conductor application step S21 is baked to form the first base electrode 61A and the second base electrode 62A. In this way, the conductor application step S21 and the hardening step S22 constitute a base electrode formation step. That is, in this embodiment, the hardening step S22 is not only a step for hardening the glass film 50, but also a part of the base electrode formation step.

[0054] In this embodiment, during heating in the curing step S22, the Kirkendall effect caused by the difference in diffusion speed between the first internal electrode 41 and the first base electrode 61A attracts palladium contained in the first internal electrode 41 to the first base electrode 61A containing silver. As a result, the first penetration portion 71 extends from the first internal electrode 41 toward the first base electrode 61A through the glass film 50, connecting the first internal electrode 41 to the first base electrode 61A. The same applies to the second penetration portion 72 connecting the second internal electrode 42 to the second base electrode 62A.

[0055] Next, a plating step S23 is performed. The first base electrode 61A and the second base electrode 62A are electroplated. Specifically, in the plating step S23, nickel is first electroplated. As a result, a nickel layer of the first metal layer 61B is formed on the surface of the first base electrode 61A. Also, a nickel layer of the second metal layer 62B is formed on the surface of the second base electrode 62A.

[0056] As described above, at the time of plating step S23, glass film 50 has through-hole 51. Therefore, a part of element body 20 is exposed to the outside through through-hole 51. Then, part of element body 20 exposed from through-hole 51 is eroded by the plating solution used in nickel electroplating. As a result, depression 26 is formed in the part of element body 20 exposed from through-hole 51.

[0057] In the plating step S23, next, tin electroplating is performed. As a result, a tin layer of the first metal layer 61B is formed on the surface of the nickel layer of the first metal layer 61B. Also, a nickel layer of the second metal layer 62B is formed on the surface of the nickel layer of the second metal layer 62B. Furthermore, since the element body 20 is a semiconductor, the inside of the depressions 26 is also plated. Therefore, a filler 63 made of tin is formed in some depressions 26B of the multiple depressions 26. In this manner, the electronic component 10 is formed.

[0058] (About the comparative test) Here, the test results of a thermal shock test, an impact film peeling test, and a migration test were compared for Examples 1 to 6 of electronic component 10 manufactured by the above-mentioned manufacturing method and an electronic component of a comparative example.

[0059] 13, in the electronic component 10 of Example 1, the thickness of the nickel layer in the first external electrode 61 and the second external electrode 62 is 2 μm. The opening area of ​​the recess 26 in the electronic component 10 of Example 1 is 1.8 μm. 2 The area ratio of the recesses 26 in the electronic component 10 of Example 1 is 0.1%. The recess volume of the recesses 26 in the electronic component 10 of Example 1 is 0.5 μm 3 It is.

[0060] In electronic component 10 of Example 2, the thickness of the nickel layer in first external electrode 61 and second external electrode 62 is 4 μm. The opening area of ​​depression 26 in electronic component 10 of Example 2 is 7.1 μ2. The area ratio of depression 26 in electronic component 10 of Example 2 is 0.5%. The depression volume of depression 26 in electronic component 10 of Example 2 is 4.1 μm 3 It is.

[0061] In the electronic component 10 of Example 3, the thickness of the nickel layer in the first external electrode 61 and the second external electrode 62 is 6 μm. The opening area of ​​the recess 26 in the electronic component 10 of Example 3 is 28.5 μm. 2 The area ratio of the recesses 26 in the electronic component 10 of Example 3 is 1.8%. The recess volume of the recesses 26 in the electronic component 10 of Example 3 is 31.8 μm 3 It is.

[0062] In the electronic component 10 of Example 4, the thickness of the nickel layer in the first external electrode 61 and the second external electrode 62 is 8 μm. The opening area of ​​the recess 26 in the electronic component 10 of Example 4 is 114.7 μm. 2 The area ratio of the recesses 26 in the electronic component 10 of Example 4 is 6.8%. The recess volume of the recesses 26 in the electronic component 10 of Example 4 is 246.9 μm 3 It is.

[0063] In the electronic component 10 of Example 5, the thickness of the nickel layer in the first external electrode 61 and the second external electrode 62 is 10 μm. The opening area of ​​the recess 26 in the electronic component 10 of Example 5 is 429.0 μm. 2 The area ratio of the recess 26 in the electronic component 10 of Example 5 is 45.4%. The recess volume of the electronic component 10 of Example 5 is 1684.1 μm 3 It is.

[0064] In the electronic component 10 of Example 6, the thickness of the nickel layer in the first external electrode 61 and the second external electrode 62 is 12 μm. The opening area of ​​the recess 26 in the electronic component 10 of Example 6 is 1963.5 μm. 2 The area ratio of the recesses 26 in the electronic component 10 of Example 6 is 58.6%. The recess volume of the recesses 26 in the electronic component 10 of Example 6 is 16493.4 μm 3 It is.

[0065] The electronic component of the comparative example was manufactured by omitting the water immersion step S19 described above. Therefore, the electronic component of the comparative example does not have any through holes 51 or recesses 26. In addition, in the electronic component of the comparative example, the nickel layer of the first external electrode 61 and the second external electrode 62 has a thickness of 2 μm.

[0066] The thermal shock test was performed as follows. First, the number of samples of electronic components to be evaluated was 30. Next, the electronic components to be evaluated were mounted on a board. Next, the board on which the electronic components were mounted was subjected to a temperature change from -55°C to 125°C, which was regarded as one cycle of thermal shock, and this was performed 100 cycles. After that, if the number of cracks in the glass film 50 increased compared to before the thermal shock was applied, it was judged as NG (No Good), and if there was no change, it was judged as G (Good).

[0067] The impact film peeling test was performed as follows. First, the number of samples of electronic components to be evaluated was 1000. Next, the electronic components to be evaluated were placed in a container, and the container was swung so that the components rubbed against each other. After that, if the number of electronic components in which the glass film 50 was partially peeled off from the element body 20 was 10 or more out of the 1000 electronic components, it was rated as NG, and if the number was less than 10, it was rated as G.

[0068] The migration test was carried out as follows. First, 18 samples of electronic components were evaluated. Next, the electronic components to be evaluated were mounted on a board. Next, 72 hours were allowed to pass at a temperature of 125°C and humidity of 95%, with an applied voltage of 3.2V or less. After that, the presence or absence of short circuits between the external electrodes due to migration was evaluated. If migration occurred in one or more of the 18 electronic components, it was rated as NG, and if migration occurred in zero, it was rated as G.

[0069] The evaluation result of the thermal shock test for electronic components 10 of Examples 1 to 6 was G. Also, the evaluation result of the impact film peeling test for electronic components 10 of Examples 1 to 6 was G. On the other hand, the evaluation result of the thermal shock test for the electronic component of the comparative example was NG. Also, the evaluation result of the impact film peeling test for the electronic component of the comparative example was NG.

[0070] When a crack occurs in glass film 50 during the thermal shock test, the impact must have been concentrated at the location on the surface of element body 20 that corresponds to the crack in glass film 50. When glass film 50 peels off from element body 20, a crack occurs in glass film 50 as the starting point of the peeling. Therefore, the impact must have been concentrated at the location on the surface of element body 20 that corresponds to the starting point of the peeling of glass film 50. In other words, the fact that the evaluation results of the thermal shock test and the evaluation results of the impact film peeling test are both G means that the impact can be prevented from being concentrated at a specific location on the surface of element body 20.

[0071] Furthermore, the evaluation result of the migration test for electronic components 10 of examples 1 to 5 was G. On the other hand, the evaluation result of the migration test for electronic component 10 of example 6 was NG.

[0072] (Operations and Effects of the Embodiments) (1) According to the above embodiment, even if an impact acts on the outer surface 21 of the element body 20, the impact is divided at the recess 26. This prevents the impact from concentrating on a specific location on the outer surface 21 of the element body 20. In addition, because part of the outer edge and part of the inner surface of the recess 26 are curved, the direction of the impact is likely to be dispersed in these curved portions. Furthermore, because the inner surface of the recess 26 is not covered with the glass film 50, it is also possible to prevent an external impact from acting on a specific location on the inner surface of the recess 26 through the glass film 50.

[0073] (2) According to the above embodiment, each of the multiple recesses 26 is connected to the through-hole 51 of the glass film 50. Therefore, as in the above-described manufacturing method, the recesses 26 can be formed in the plating step S23 for forming the first external electrode 61 and the second external electrode 62, and therefore there is no need to employ a separate step for forming the recesses 26.

[0074] (3) According to the above embodiment, filler 63 is present in the internal space of recess 26B. Filler 63 is a relatively soft metal and functions as a buffer that absorbs impacts. Therefore, even if a force is applied from the outside of electronic component 10 toward recess 26B, the impact can be absorbed by filler 63. Therefore, it is possible to reduce the direct transmission of force from the outside of electronic component 10 to element body 20.

[0075] (4) According to the above embodiment, the opening area of ​​the recess 26 is 1 μm 2 More than 2000μm 2 That is, the opening area of ​​the recess 26 is not excessively large, thereby preventing the strength of the element body 20 from being adversely affected by the recess 26 being too large.

[0076] (5) According to the above embodiment, the area ratio of the dents 26 is not less than 0.1% and not more than 60.0%. With an area ratio in this range, it is possible to prevent a plurality of dents 26 from joining together to form a large dent, which would otherwise adversely affect the strength of the element body 20.

[0077] (6) According to the above embodiment, the volume of the inner space of the recess 26 is 0.1 μm 3 More than 20000μm 3 If the recess volume is within this range, it is unlikely that the recess 26 will reach the first internal electrode 41 or the second internal electrode 42.

[0078] (7) According to the above embodiment, the maximum depth H of the recess 26A with respect to the opening diameter D of the recess 26A is 25% or more. Since the recess 26A has a certain degree of maximum depth H in this manner, it is possible to reliably exert the effect of dividing a force when a force acts on the surface of the element body 20. Furthermore, the maximum depth H of the recess 26A with respect to the opening diameter D of the recess 26A is 50% or less. Therefore, the recess 26A as a whole has a shape that is elongated in the direction along the outer surface 21. This makes it possible to prevent the occurrence of cracks or the like in the element body 20 starting from the recess 26.

[0079] <Other embodiments> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined and implemented within a range that does not cause technical contradiction.

[0080] In the above embodiment, the electronic component 10 is not limited to a negative temperature coefficient thermistor component. For example, as long as the electronic component 10 has some kind of wiring inside the element body 20, it may be a thermistor component other than a negative temperature coefficient thermistor component, a multilayer capacitor component, or an inductor component.

[0081] 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 shape other than a quadrangular column shape having a central axis CA. The element body 20 may also be a 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 portion and flange portions provided on each end of the winding core portion.

[0082] The material of the element body 20 is not limited to the examples in the above embodiments. For example, the material of the element body 20 may be a composite body of resin and metal powder. The outer surface 21 of the element body 20 may not have a boundary surface 23 and a corner surface 24. For example, if the boundary between adjacent flat surfaces 22 on the outer surface 21 of the element body 20 is not chamfered, there is no curved surface at the boundary. Therefore, in such a case, the boundary surface 23 and the corner surface 24 may not exist.

[0083] In the above embodiment, the shape of the first internal electrode 41 and the second internal electrode 42 is not important as long as the shape ensures electrical conduction with the corresponding first external electrode 61 and second external electrode 62. In addition, the number of first internal electrodes 41 and second internal electrodes 42 is not important, and the number of internal electrodes may be one, or three or more.

[0084] The thickness of the nickel layer of the first external electrode 61 may be less than 0.5 μm or more than 10 μm. According to the manufacturing method of the above embodiment, the recesses 26 are formed by electroplating nickel. If the thickness of the nickel layer of the first external electrode 61 is set to 0.5 μm or more and 10 μm or less, the size of the recesses 26 can be formed within a preferable range from the viewpoint of migration testing. On the other hand, for example, even if the thickness of the nickel layer of the first external electrode 61 is greater than 10 μm, the evaluation results of the thermal shock test and the shock film peeling test were good. That is, even if the thickness of the nickel layer of the first external electrode 61 is greater than 10 μm, it is possible to prevent the impact from being concentrated on a specific location on the surface of the element body 20. The same is true for the second external electrode 62.

[0085] 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, and the first metal layer 61B may not have a two-layer structure. If the first metal layer 61B has a nickel layer, the recess 26 can be formed in the element body 20 by the manufacturing method exemplified in the embodiment. The same applies to the second external electrode 62.

[0086] In the above embodiment, the combination of materials of the first internal electrode 41 and the first base electrode 61A is not limited to the combination of palladium and silver. For example, it may be a combination of copper and nickel, copper and silver, silver and gold, nickel and cobalt, or nickel and gold. For example, it may be a combination of one being silver and the other being silver and palladium. For example, it may be a combination of one being palladium and the other being silver and palladium, or it may be a combination of one being copper and the other being silver and palladium. For example, it may be a combination of one being gold and the other being silver and palladium.

[0087] 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 forming step, for example, the first end face 22A side of the element body 20 may be polished to physically remove a part of the glass film 50 so that the first internal electrode 41 is exposed. Then, the base electrode forming step may be performed to connect the first internal electrode 41 and the first base electrode 61A. Also, for example, after forming the first base electrode 61A, the 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 point is also the same for the combination of materials of the second internal electrode 42 and the second base electrode 62A.

[0088] The location of the first external electrode 61 is not limited to the example in the above embodiment. For example, the first external electrode 61 may be disposed only on the first end surface 22A and one side surface 22C. The same applies to the second external electrode 62.

[0089] The glass film 50 does not have to cover the first end face 22A and the second end face 22B. The area covered by the glass film 50 may be changed as appropriate depending on the shape of the element body 20, the positions of the first external electrode 61 and the second external electrode 62, etc.

[0090] In the portion of glass film 50 that is covered with first base electrode 61A, the glass of glass film 50 may diffuse into the glass of first base electrode 61A, so that the two become integrated.

[0091] Regarding the depression 26, the maximum depth H of the depression 26 with respect to the length of the opening diameter D of the depression 26 may be less than 25% or more than 50%. In this way, the relationship between the opening diameter D and the maximum depth H may be changed as appropriate depending on the shape of the depression 26. For example, a plurality of depressions 26 may be connected, or the depression 26 may be considerably deep.

[0092] For the depression 26, the depression volume is 20000 μm 3 For example, when element body 20 is appropriately large, the strength of element body 20 can be ensured even if the volume of the recess is appropriately large.

[0093] Regarding the depressions 26, the area ratio of the depressions 26 may be greater than 60.0%. For example, if the size of the element 20 is appropriately large, the strength of the element 20 can be ensured even if the area ratio of the depressions 26 is appropriately large.

[0094] The opening area of ​​the recess 26 is 2000 μm 2 For example, if the size of element body 20 is appropriately large, the strength of element body 20 can be ensured even if the opening area is appropriately large.

[0095] The plurality of recesses 26 may have only one of recesses 26A having no internal space and recesses 26B having an internal space containing filler 63. For example, the plurality of recesses 26 may not have recesses 26B having an internal space containing filler 63.

[0096] Filler 63 does not have to cover the entire inner surface of recess 26B. That is, filler 63 may cover only a portion of the inner surface of recess 26B. In this case, filler 63 does not protrude from recess 26B. That is, when electronic component 10 is viewed in a direction perpendicular to outer surface 21, filler 63 may cover an area narrower than recess 26B. It is sufficient that filler 63 is located at least in the internal space of recess 26B.

[0097] With regard to through hole 51, when electronic component 10 is viewed in a direction perpendicular to outer surface 21, through hole 51 may be larger or smaller than the outer edge of depression 26. If through hole 51 is smaller than the outer edge of depression 26, glass film 50 appears to be floating above the inner surface of depression 26. Even in this case, glass film 50 is not in contact with the inner surface of depression 26, and therefore the inner surface of depression 26 is not covered with glass film 50.

[0098] The manufacturing method of electronic component 10 is not limited to the example of the above embodiment. For example, recess 26 may be formed by mechanically cutting, or glass film 50 may be formed by attaching a sheet-like thin film to element body 20. In this case, glass film 50 does not need to have through-hole 51. [Explanation of symbols]

[0099] 10. Electronic components 20…Base 21...Outer surface 26…Hollow 41...First internal electrode 42…Second internal electrode 50…Glass membrane 51...Through hole 61...First external electrode 62…Second external electrode 63...Filling 71…First penetration 72…Second penetration 81...Reaction vessel 82...Solvent 83...Aqueous solution 84…Polymer 85...Metal alkoxide

Claims

1. The semiconductor device comprises an element body, wiring located inside the element body, a glass film covering an outer surface of the element body, and a filler, The element body has a recess recessed from the outer surface, The inner surface of the cavity is not covered with the glass film, When the depression is viewed in a direction perpendicular to the outer surface, at least a portion of an outer edge of the depression is curved; When the depression is viewed in a cross section perpendicular to the outer surface, at least a portion of the inner surface of the depression is curved; The glass film has a through hole penetrating the glass film, The recess is connected to the through hole, The filling material is located in the internal space of the depression, and a portion of the filling material extends to the outside of the outer edge of the depression and covers a portion of the glass film. Electronic components.

2. an internal electrode as the wiring; an external electrode electrically connected to the internal electrode and exposed to an outside of the electronic component; The material of the body includes a semiconductor, the external electrode has a tin layer containing tin, The material of the filler contains tin. The electronic component according to claim 1 .

3. The external electrode has a nickel layer containing nickel, The thickness of the nickel layer is 0.5 μm or more and 10 μm or less. The electronic component according to claim 2 .

4. The semiconductor device comprises an element body, wiring located inside the element body, and a glass film covering an outer surface of the element body, The element body has a recess recessed from the outer surface, The inner surface of the cavity is not covered with the glass film, When the depression is viewed in a direction perpendicular to the outer surface, at least a portion of an outer edge of the depression is curved; When the depression is viewed in a cross section perpendicular to the outer surface, at least a portion of the inner surface of the depression is curved; When the depression is viewed in a direction perpendicular to the outer surface, the area of ​​a region surrounded by the outer edge of the depression is defined as the opening area of ​​the depression. The opening area of ​​the recess is 1 μm 2 or more and 2000 μm 2 or less. Electronic components.

5. The semiconductor device comprises an element body, wiring located inside the element body, and a glass film covering an outer surface of the element body, The element body has a recess recessed from the outer surface, The inner surface of the cavity is not covered with the glass film, When the depression is viewed in a direction perpendicular to the outer surface, at least a portion of an outer edge of the depression is curved; When the depression is viewed in a cross section perpendicular to the outer surface, at least a portion of the inner surface of the depression is curved; When the depression is viewed in a direction perpendicular to the outer surface, the area of ​​a region surrounded by the outer edge of the depression is defined as the opening area of ​​the depression. The ratio of the total opening area of ​​all the recesses to the area of ​​the outer surface is 0.1% or more and 60.0% or less. Electronic components.

6. The semiconductor device comprises an element body, wiring located inside the element body, and a glass film covering an outer surface of the element body, The element body has a recess recessed from the outer surface, The inner surface of the cavity is not covered with the glass film, When the depression is viewed in a direction perpendicular to the outer surface, at least a portion of an outer edge of the depression is curved; When the depression is viewed in a cross section perpendicular to the outer surface, at least a portion of the inner surface of the depression is curved; The volume of the internal space of each of the depressions is 0.1 μm 3 or more and 20,000 μm 3 or less. Electronic components.

7. The semiconductor device comprises an element body, wiring located inside the element body, and a glass film covering an outer surface of the element body, The element body has a recess recessed from the outer surface, The inner surface of the cavity is not covered with the glass film, When the depression is viewed in a direction perpendicular to the outer surface, at least a portion of an outer edge of the depression is curved; When the depression is viewed in a cross section perpendicular to the outer surface, at least a portion of the inner surface of the depression is curved; When viewed in a cross section perpendicular to the outer surface, passing through the geometric center of the outer edge of the depression, and having a longest opening diameter, which is the distance from the outer edge of the depression to the outer edge on the opposite side of the geometric center, the maximum depth of the depression relative to the length of the opening diameter is 25% or more and 50% or less. Electronic components.

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