Electronic component

Abstract

This electronic component (10) is provided with an element body (20) and a glass film (51). The glass film (51) covers an outer surface (21) of the element body (20). The material of the glass film (51) contains an organic silane compound. The outer surface (21) of the element body (20) has a recess section (24) which is a place recessed with respect to the surroundings thereof. The arithmetic average roughness of the portion of an outer surface (53) of the glass film (51) that covers the recess (24) is 3 to 200 nm.

Description

Electronic Components

[0001] The present disclosure relates to electronic components.

[0002] The electronic component disclosed in Patent Document 1 includes an element body and a glass film. The glass film covers the outer surface of the element body.

[0003] Patent No. 4868019

[0004] In electronic components such as those disclosed in Patent Document 1, the outer surface of the element body may have a recess, which is a portion recessed relative to the surrounding area. The inner surface of the recess may have minute gaps and cracks formed during the process of forming the recess. Therefore, liquids such as plating solutions may easily penetrate into the element body through the recess. To prevent liquids from penetrating into the element body through the recess, it is necessary to improve the liquid barrier properties of the glass film covering the recess.

[0005] In order to solve the above-described problems, one aspect of the present disclosure is an electronic component comprising an element body and a glass film covering an outer surface of the element body, wherein the material of the glass film contains an organosilane compound, the outer surface of the element body has a recess that is recessed relative to its surroundings, and the arithmetic mean roughness of the outer surface of the glass film at a portion covering the recess is 3 nm or more and 200 nm or less.

[0006] The liquid barrier properties of the glass film covering the recesses can be improved.

[0007] FIG. 1 is a perspective view of an electronic component. FIG. 2 is a side view of the electronic component. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. FIG. 4 is an enlarged cross-sectional view of an element body. FIG. 5 is an enlarged cross-sectional view of a recess. FIG. 6 is an explanatory diagram illustrating the manufacturing process of an electronic component. FIG. 7 is an explanatory diagram illustrating a manufacturing method of an electronic component. FIG. 8 is an explanatory diagram illustrating a manufacturing method of an electronic component. FIG. 9 is an explanatory diagram illustrating a manufacturing method of an electronic component. FIG. 10 is an explanatory diagram illustrating a manufacturing method of an electronic component.

[0008] An embodiment of an electronic component will now be described with reference to the drawings. The drawings may show components enlarged for ease of understanding. The dimensional proportions of the components may differ from those in the actual components or from those in other drawings.

[0009] 1, the electronic component 10 is, for example, a surface-mount type negative temperature coefficient thermistor component mounted on a circuit board, etc. Note that a negative temperature coefficient thermistor component has the characteristic that its resistance value decreases as the temperature increases.

[0010] 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 referred to as a first axis X. One of the axes perpendicular to the first axis X is referred to as a second axis Y. An axis perpendicular to the first axis X and the second axis Y is referred to as a third axis Z. One of the directions along the first axis X is referred to as a first positive direction X1, and the direction along the first axis X that is opposite to the first positive direction X1 is referred to as a first negative direction X2. One of the directions along the second axis Y is referred to as a second positive direction Y1, and the direction along the second axis Y that is opposite to the second positive direction Y1 is referred to as a second negative direction Y2. One of the directions along the third axis Z is referred to as a third positive direction Z1, and the direction along the third axis Z that is opposite to the third positive direction Z1 is referred to as a third negative direction Z2.

[0011] The outer surface 21 of the element body 20 has six flat surfaces. Note that the "surface" of the element body 20 here refers to what can be observed as a surface 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 using a microscope or the like, the surface is expressed as a flat surface or a curved surface.

[0012] The six flat surfaces face in different directions. The six flat surfaces are roughly divided into a first end surface 22A facing the first positive direction X1, a second end surface 22B facing the first negative direction X2, and four side surfaces 22C. The four side surfaces 22C are respectively a surface facing the third positive direction Z1, a surface facing the third negative direction Z2, a surface facing the second positive direction Y1, and a surface facing the second negative direction Y2.

[0013] The boundary portions between two adjacent flat surfaces and the boundary portions between three adjacent flat surfaces on the outer surface 21 of the element body 20 are curved. That is, the corners of the element body 20 are rounded and chamfered. In Figures 1 and 2, the outer surface 53 of a glass film 51 (described later) is identified with the outer surface 21 of the element body 20 and is given a reference numeral.

[0014] 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. The material of the element body 20 is a ceramic obtained by sintering a metal oxide containing one or more elements selected from Mn, Fe, Ni, Co, Ti, Ba, Al, and Zn. Therefore, as shown in FIG. 4 , the element body 20 has a plurality of voids 23 therein. These voids 23 are mainly present at the boundaries between grains constituting the sintered element body 20. Note that the voids 23 are not shown in FIG. 3 .

[0015] 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 both embedded inside the element body 20.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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, they are arranged in the order of the first internal electrode 41, the second internal electrode 42, the first internal electrode 41, and the second internal electrode 42 in the second positive direction Y1. In this embodiment, the distances between the internal electrodes in the direction along the second axis Y are equal.

[0020] 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.

[0021] 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. That is, the end of the first internal electrode 41 on the first positive direction X1 side is exposed at the first end surface 22A of the element body 20. 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. That is, the end of the first internal electrode 41 on the first negative direction X2 side is exposed at the second end surface 22B of the element body 20. 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.

[0022] As shown in FIG. 3 , the electronic component 10 includes a glass film 51. The glass film 51 covers the outer surface 21 of the element body 20. In this embodiment, the glass film 51 covers all four side surfaces 22C of the outer surface 21 of the element body 20. The main material of the glass film 51 is insulating glass. Therefore, the glass film 51 contains silicon dioxide. The glass film 51 also contains an organosilane compound having a carbon chain with three or more carbon atoms. The organosilane compound has one or more functional groups selected from, for example, an epoxy group, a mercapto group, an amino group, a vinyl group, and a methacryl group. Specifically, the organosilane compound is 3-glycidoxypropyltrimethoxysilane (hereinafter referred to as "GPTMS"). Note that GPTMS has an epoxy group as a functional group.

[0023] 4 , the electronic component 10 includes a filling portion 52. The filling portion 52 fills at least some of the voids 23. In this embodiment, the filling portion 52 fills almost all of the voids 23 in the element body 20. The material of the filling portion 52 is the same as that of the glass film 51.

[0024] When a cross section including the geometric center GC of the element body 20 is imaged using an electron microscope or the like, if the filling portion 52 fills the voids 23 closest to the geometric center GC, it can be said that the filling portion 52 fills substantially all of the voids 23 in the element body 20. As shown in FIG. 3 , the geometric center GC of the element body 20 is the geometric center point of the element body 20 including the first internal electrodes 41 and second internal electrodes 42 located inside the element body 20. However, some deviation from the geometric center GC is permitted depending on factors such as the processing accuracy when cutting the element body 20. Specifically, even if the deviation from the geometric center GC in the strict sense is about 5% of the dimension of the element body 20 in the direction along the first axis X, it is still considered to be the geometric center GC. The same applies to deviations in the direction along the second axis Y and the direction along the third axis Z.

[0025] 3, the electronic component 10 includes a first external electrode 61 and a second external electrode 62. In FIGS. 1 to 3, the first external electrode 61 and the second external electrode 62 are illustrated by two-dot chain lines.

[0026] 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 a portion of the outer surface 21 of the element body 20, including the first end face 22A. Specifically, the first base electrode 61A covers the first end face 22A of the element body 20, and also covers portions of the four side faces 22C facing the first positive direction X1 from above the glass film 51. In other words, the first base electrode 61A is a five-sided electrode. In this embodiment, the material of the first base electrode 61A is a resin electrode. More specifically, the material of the first base electrode 61A is a mixture of organic resin and silver particles.

[0027] The first metal layer 61B externally covers the first base electrode 61A. 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 consisting of a nickel-plated layer and a tin-plated layer in this order from the first base electrode 61A side. The first external electrode 61 is connected to the end of the first internal electrode 41 on the first positive direction X1 side.

[0028] 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 a portion of the outer surface 21 of the element body 20, including the second end face 22B. Specifically, the second base electrode 62A covers the second end face 22B of the element body 20 and also covers portions of the four side faces 22C facing the first negative direction X2 from above the glass film 51. In other words, the second base electrode 62A is a five-sided electrode. In this embodiment, the material of the second base electrode 62A is a resin electrode. More specifically, the material of the second base electrode 62A is a mixture of organic resin and silver particles.

[0029] The second metal layer 62B externally covers the second base electrode 62A. Therefore, the second metal layer 62B is laminated on the second base electrode 62A. Specifically, like the first metal layer 61B, the second metal layer 62B has a two-layer structure of a nickel-plated layer and a tin-plated layer. The second external electrode 62 is connected to the end of the second internal electrode 42 on the first negative direction X2 side.

[0030] The second external electrode 62 does not reach the first external electrode 61 on the side surface 22C, and is spaced apart from the first external electrode 61 in the direction along the first axis X. In addition, the first external electrode 61 and the second external electrode 62 are not stacked in the central portion of the side surface 22C of the element body 20 in the direction along the first axis X, and the glass film 51 is exposed.

[0031] (Regarding Recesses) As shown in Figure 5, the outer surface 21 of the element body 20 has one or more recesses 24. The recesses 24 are recessed toward the inside of the element body 20 relative to the surrounding area. The glass film 51 described above also covers the recesses 24 on the outer surface 21 of the element body 20. The glass film 51 conforms to the recessed shape of the recesses 24 to some extent. In other words, the outer surface 53 of the glass film 51 covering the recesses 24 is recessed toward the inside of the element body 20 relative to the surrounding area. The recesses 24 are caused by falling off of ceramic particles, cracks, and chips in the element body 20, etc. A recess 24 is defined as a recess having a maximum depth H that is 10 times or more the arithmetic mean roughness of the outer surface 21 of the element body 20.

[0032] The maximum depth H of the recess 24 is the depth at the deepest point of the recess 24. Specifically, the maximum depth H of the recess 24 is calculated as follows. First, the element body 20 is ground in a direction perpendicular to the outer surface 21 of the element body 20. Grinding is performed, for example, by focused ion beam processing. Next, an image of the ground cross section of the element body 20 is taken using an electron microscope or the like. Then, as shown in FIG. 5 , a tangent line CL is drawn on the imaged ground cross section, circumscribing both of the outer surfaces 21 of the element body 20 on both sides of the recess 24. Note that a portion of the tangent line CL may coincide with the outer surface 21 of the element body 20. In this case, the length from the tangent line CL to the inner surface of the recess 24 in a direction perpendicular to the tangent line CL is defined as the depth of the recess 24. Next, the element body 20 is further ground from the ground cross section by a predetermined imaging pitch, and a new ground cross section of the element body 20 is imaged. Note that the imaging pitch is, for example, 10 nm. The maximum depth of the same recess 24 on this new ground cross section is measured. In this manner, the imaging of the ground cross section of the element 20 and the measurement of the maximum depth of the recess 24 are repeated. The largest value among the maximum depths of the recess 24 on each ground cross section obtained in this manner is taken as the maximum depth H of the entire recess 24.

[0033] The maximum depth H of the recess 24 calculated by the above method is 0.3 μm or more and 3 μm or less. Furthermore, the maximum dimension L of the line segment LS connecting two points on the opening edge 25 of the recess 24 is 0.5 μm or more and 20 μm or less.

[0034] The opening edge 25 of the recess 24 is defined as follows: First, a tangent line CL is drawn on a ground cross-sectional image of the element body 20 captured using an electron microscope or the like using the method described above. Then, of the points of contact between this tangent line CL and the outer surface 21 of the element body 20, the edge closest to the center of the recess 24 is defined as the opening edge 25.

[0035] (Regarding the glass film covering the recesses) The portion of the outer surface 21 of the element body 20 excluding the recesses 24 is defined as the flat surface 26. In this case, the arithmetic mean roughness of the outer surface 53 of the glass film 51 at the portion covering the recesses 24 is greater than the arithmetic mean roughness of the outer surface 53 of the glass film 51 at the portion covering the flat surface 26. Furthermore, the arithmetic mean roughness of the portion of the outer surface 53 of the glass film 51 covering the recesses 24 is 3 nm or more and 200 nm or less. More preferably, the arithmetic mean roughness is 100 nm or less. Even more preferably, the arithmetic mean roughness is 10 nm or more and 30 nm or less.

[0036] The arithmetic mean roughness of the portion of the outer surface 53 of the glass film 51 covering the recess 24 is calculated as follows. First, a tangent line CL is drawn on the ground cross-sectional image of the element body 20 captured using an electron microscope or the like using the method described above. Then, the measurement range is the range between the opening edges 25 of one recess 24 on the ground cross-section, and a range of 500 nm in the direction along the tangent line CL. Then, the arithmetic mean roughness of the glass film 51 at the portion covering the recess 24 in the measurement range is calculated by image processing.

[0037] The average thickness T2 of the glass film 51 at the portion covering the flat surface 26 is 15 nm or more and 1000 nm or less. More preferably, the average thickness T2 of the glass film 51 at the portion covering the flat surface 26 is 15 nm or more and 500 nm or less. Even more preferably, the average thickness T2 of the glass film 51 at the portion covering the flat surface 26 is 20 nm or more and 200 nm or less.

[0038] Furthermore, the average thickness T1 of glass film 51 at the portion covering recess 24 is greater than the average thickness T2 of glass film 51 at the portion covering flat surface 26. For example, the average thickness T1 of glass film 51 at the portion covering recess 24 is approximately 106 nm. The average thickness T2 of glass film 51 at the portion covering flat surface 26 is 33 nm.

[0039] The thickness of the glass film 51 is calculated as follows. First, an image of the ground cross section of the element body 20 is taken using an electron microscope or the like according to the method described above. A measurement range of at least 10 μm in the captured image is determined in the direction along the outer surface 53 of the glass film 51. The cross-sectional area of ​​the glass film 51 in the measurement range is then calculated by image processing. The cross-sectional area of ​​the glass film 51 in the measurement range is then divided by the length of the measurement range in the direction along the outer surface 53 of the glass film 51 to calculate the average thickness of the glass film 51. In other words, the average thickness of the glass film 51 is the average value of the thicknesses in the measurement range. When using the method described above to determine the thickness T1 of the glass film 51 at the location covering the recess 24, the measurement ranges are specified for multiple recesses 24, so long as the total measurement range is 10 μm or more.

[0040] (Method for Manufacturing Electronic Component) Next, a method for manufacturing electronic component 10 will be described. As shown in Figure 6, the method for manufacturing electronic component 10 includes an element body preparation step S11, an R-chamfering step S12, a solvent introduction step S13, and a catalyst introduction step S14. The method for manufacturing electronic component 10 also includes an element body introduction step S15, a solution introduction step S16, a filling / film-forming step S17, a drying step S18, a first curing step S19, and an internal electrode exposure step S20. The method for manufacturing electronic component 10 also includes a conductor application step S21, a second curing step S22, and a plating step S23.

[0041] First, an element body preparation step S11 is performed. In the element body preparation step S11, a rectangular parallelepiped element body 20 having six flat surfaces is prepared. That is, the element body 20 at this stage is the element body 20 in a state before R-chamfering. For example, first, multiple ceramic sheets that will become the element body 20 are prepared. The sheets are thin plates. 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 manner, the ceramic sheets and the conductive paste are laminated. The ceramic sheets are then cut to a predetermined size to form the element body 20 as an unfired laminate. The unfired element body 20 is then fired at a high temperature to prepare the element body 20. Note that the ceramic sheets have multiple voids therein. Therefore, the prepared element body 20 has multiple voids 23 therein.

[0042] Next, as shown in Fig. 6, an R-chamfering process S12 is performed. In the R-chamfering process S12, curved surfaces are formed at the boundary portions between two adjacent flat surfaces and at the boundary portions between three adjacent flat surfaces of the laminate prepared in the element preparation process S11. For example, the corners of the laminate are R-chamfered by barrel polishing, thereby forming curved surfaces at the boundary portions.

[0043] Next, as shown in Fig. 6, a solvent introduction step S13 is performed. As shown in Fig. 7, in the solvent introduction step S13, 2-propanol is introduced into a reaction vessel 81 as a solvent 82. Next, as shown in Fig. 6, a catalyst introduction step S14 is performed. As shown in Fig. 8, 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 hydroxide ions, which function as a catalyst for promoting the hydrolysis of a metal alkoxide, which will be described later.

[0044] Next, an element body introduction step S15 is performed as shown in Fig. 6. In the element body introduction step S15, as shown in Fig. 9, a plurality of element bodies 20 formed in advance in the R-chamfering step S12 as described above are introduced into a reaction vessel 81.

[0045] Next, a solution introduction step S16 is performed as shown in FIG. 6 . As shown in FIG. 10 , in the solution introduction step S16, a mixed solution 84 of a metal alkoxide and an organosilane compound is introduced into a reaction vessel 81. The metal alkoxide is liquid tetraethyl orthosilicate (hereinafter referred to as "TEOS"). TEOS is also called tetraethoxysilane. The organosilane compound is liquid GPTMS. The GPTMS is introduced at a weight ratio of 0.12 or more to 1 but less than 1 relative to the TEOS. Specifically, the GPTMS is introduced at a weight ratio of approximately 0.43 relative to the TEOS.

[0046] In this embodiment, the amount of mixed liquid 84 to be introduced in solution introduction step S16 is calculated based on the porosity of the element body 20 and the area of ​​the outer surface 21 of the element body 20 introduced in element body introduction step S15. Specifically, first, for each element body 20, the sum of the amount of the solution required to fill the voids 23 of the element body 20 and the amount of the solution required to form a glass film 51 covering the outer surface 21 of the element body 20 is calculated. This sum is multiplied by the number of element bodies 20 introduced in element body introduction step S15 to calculate the required amount of mixed liquid 84. The porosity of the element body 20 is defined as the ratio of the total volume of the voids 23 to the volume of the element body 20.

[0047] Next, as shown in FIG. 6 , the filling / film-forming step S17 is performed. First, in the filling / film-forming step S17, the stirring of the solvent 82 initiated in the solvent-introducing step S13 is continued for a predetermined time. As a result, the metal alkoxide undergoes condensation polymerization by hydrolysis due to hydroxide ions, which serve as a catalyst. The metal alkoxide particles generated by this condensation polymerization reaction maintain a small volume per molecule for a relatively long period of time. Therefore, first, some of the metal alkoxide enters the voids 23 inside the element 20 together with the solution. Then, condensation polymerization of the metal alkoxide progresses within the voids 23, causing the metal alkoxide particles to grow larger. As a result, a filling portion 52 is formed within the voids 23 of the element 20.

[0048] Meanwhile, the portion of the metal alkoxide that did not penetrate the voids 23 undergoes condensation polymerization outside the element body 20, resulting in larger particles. The metal alkoxide particles then associate with the organosilane compound. That is, the metal alkoxide particles are bonded to each other by intermolecular forces. The associated metal alkoxide adheres to the outer surface 21 of the element body 20. The metal alkoxides attached to the outer surface 21 of the element body 20 then undergo condensation polymerization to form a glass film 51. At this time, the metal alkoxide and the solvent 82 are likely to come into contact with each other on the flat surface 26 of the outer surface 21 of the element body 20. Therefore, the outer surface 53 of the glass film 51 covering the flat surface 26 is smoothed to a certain extent. On the other hand, the metal alkoxide and the solvent 82 are less likely to come into contact with each other on the inner surfaces of the recesses 24. Therefore, the surface roughness of the outer surface 53 of the glass film 51 covering the recess 24 is rougher than the surface roughness of the glass film 51 covering the flat surface 26, reflecting the shape of the metal alkoxide aggregate deposited on the inner surface of the recess 24.

[0049] Thus, in the filling / film-forming step S17, a sol-like filling portion 52 is formed and a sol-like glass film 51 is formed by a liquid-phase reaction in the reaction vessel 81. Furthermore, the arithmetic mean roughness of the outer surface 53 of the glass film 51 at the portion covering the flat surface 26 of the outer surface 21 of the element body 20 is smaller than the arithmetic mean roughness of the outer surface 53 of the glass film 51 at the portion covering the recess 24.

[0050] Next, a drying step S18 is performed. In the drying step S18, first, after the filling and film-forming step S17, the element body 20 is removed from the reaction vessel 81. Next, the filling portion 52 on the sol and the sol-like glass film 51 are dried. As a result, a gel-like filling portion 52 and a gel-like glass film 51 are formed.

[0051] Next, a first hardening step S19 is performed. In the first hardening step S19, the element body 20 that has undergone the drying step S18 is baked at a temperature of 140°C or higher and 160°C or lower. Specifically, it is baked at a temperature of 150°C. This hardens the gel-like filling portion 52 and the gel-like glass film 51. That is, the glass film 51 and the filling portion 52 are entirely hardened. At this stage, the glass film 51 covers the entire outer surface 21 of the element body 20.

[0052] Next, an internal electrode exposing step S20 is performed. In the internal electrode exposing step S20, the glass film 51 covering the first end face 22A and the second end face 22B of the element body 20 is removed to expose the first internal electrode 41 and the second internal electrode 42. In this embodiment, the glass film 51 is removed by grinding with a laser over the entire first end face 22A and the entire second end face 22B of the element body 20.

[0053] Next, a conductor application step S21 is performed. In the conductor application step S21, a conductor paste is applied to a portion of the outer surface 21 of the element body 20 and a portion of the outer surface 53 of the glass film 51. Specifically, the conductor paste is applied to two locations: the glass film 51 covering the first end face 22A of the element body 20 and portions of the four side faces 22C of the element body 20 on the first positive direction X1 side, and the glass film 51 covering the second end face 22B of the element body 20 and portions of the four side faces 22C of the element body 20 on the first negative direction X2 side. In this embodiment, the conductor paste contains silver particles and an organic resin.

[0054] Next, a second curing step S22 is performed. Specifically, in the second curing step S22, the element body 20 to which the conductive paste has been applied is heated to harden the conductive paste. In this embodiment, the element body 20 is heated to approximately 200°C. The conductive paste applied in the conductor applying step S21 is then fired to form the first base electrode 61A and the second base electrode 62A.

[0055] Next, a plating step S23 is performed. In the plating step S23, a first metal layer 61B is formed on the surface of the first base electrode 61A by electroplating. A second metal layer 62B is formed on the surface of the second base electrode 62A. Although not shown, the first metal layer 61B and the second metal layer 62B are electroplated with two types of metal, nickel and tin, to form a two-layer structure. In this manner, the electronic component 10 is formed.

[0056] (Effects of this embodiment) (1) In the above embodiment, the arithmetic mean roughness of the portion of outer surface 53 of glass film 51 covering recess 24 is 3 nm or more and 200 nm or less. Outer surface 53 of glass film 51 has a certain degree of hydrophobicity and oleophobicity. When the arithmetic mean roughness of glass film 51 is within the above range, liquid is less likely to penetrate into the gaps between the minute irregularities on outer surface 53 of glass film 51. Therefore, the liquid barrier properties of glass film 51 covering recess 24 can be improved.

[0057] Furthermore, if the arithmetic mean roughness of outer surface 53 of glass film 51 is greater than 200 nm, friction is likely to occur on outer surface 53 of glass film 51, which may cause cracks or the like in glass film 51. Therefore, the arithmetic mean roughness of the portion of outer surface 53 of glass film 51 that covers recess 24 is preferably within the above-mentioned numerical range.

[0058] (2) In the above embodiment, the average value of the thickness T2 of the glass film 51 at the portion covering the flat surface 26 of the outer surface 21 of the element body 20 is 15 nm or more and 1000 nm or less. If the thickness T2 of the glass film 51 is less than 15 nm, there is a risk that a plating solution or the like may easily penetrate. Furthermore, if the thickness T2 of the glass film 51 is greater than 1000 nm, the stress acting on the glass film 51 is likely to be large. In other words, there is a risk that cracks or the like may easily occur in the glass film 51. Therefore, the thickness T2 of the glass film 51 is preferably in the above-mentioned numerical range.

[0059] (3) According to the above embodiment, the average value of the thickness T1 of the glass film 51 covering the recessed portion 24 is greater than the average value of the thickness T2 of the glass film 51 covering the flat surface 26. The thicker the thickness T2 of the glass film 51 covering the flat surface 26, the greater the stress acting on the glass film 51. That is, in this case, cracks are more likely to occur in the glass film 51 covering the flat surface 26. On the other hand, the thinner the thickness T1 of the glass film 51 covering the recessed portion 24, the lower the barrier property of the glass film 51 against liquids in the recessed portion 24. Therefore, by making the average value of the thickness T1 of the glass film 51 covering the recessed portion 24 greater than the average value of the thickness T2 of the glass film 51 covering the flat surface 26, cracks can be prevented from occurring in portions other than the recessed portion 24, while ensuring sufficient barrier property of the glass film 51 against liquids.

[0060] (4) In the above embodiment, the maximum dimension L of the line segment LS connecting two points on the opening edge 25 of the recess 24 is 0.5 μm or more and 20 μm or less. In other words, the maximum dimension of the outer diameter of the recess 24 is 0.5 μm or more and 20 μm or less. If the maximum dimension L is less than 0.5 μm, it may be difficult to form the glass film 51 on the surface of the recess 24. Furthermore, if the maximum dimension L is greater than 0.5 μm, the arithmetic mean roughness of the portion of the outer surface 53 of the glass film 51 covering the recess 24 is likely to be small. Therefore, the above numerical range is preferable for the maximum dimension of the outer diameter of the opening edge 25 of the recess 24.

[0061] (5) In the above embodiment, the maximum depth H of the recess 24 is 0.3 μm or more and 3 μm or less. If the maximum depth H of the recess 24 is less than 0.3 μm, the arithmetic mean roughness of the outer surface 53 of the glass film 51 covering the recess 24 is unlikely to fall within the preferred numerical range described in section (1). Furthermore, if the maximum depth H of the recess 24 is greater than 3 μm, for example, at a location where the inner surface of the recess 24 has a steep slope, the arithmetic mean roughness of the outer surface 53 of the glass film 51 is unlikely to fall within the preferred numerical range described in section (1). Therefore, the above-mentioned numerical range is preferred for the maximum depth H of the recess 24.

[0062] (6) In the above embodiment, the organosilane compound is a silane compound having a carbon chain with three or more carbon atoms. This makes it easier for the arithmetic mean roughness of outer surface 53 of glass film 51 covering recess 24 to fall within a suitable numerical range.

[0063] (7) If the glass film 51 covering the recess 24 were to be made thicker overall, the stress acting on the glass film 51 would increase, making cracks more likely to occur. In other words, simply making the glass film 51 covering the recess 24 thicker overall would be insufficient to improve the liquid barrier properties of the recess 24. In this embodiment, the arithmetic mean roughness of the outer surface 53 of the glass film 51 covering the recess 24 is 3 nm or more and 200 nm or less. Therefore, the liquid barrier properties of the recess 24 can be improved without making the glass film 51 excessively thick.

[0064] <Modifications> The above embodiment and the following modifications can be implemented in combination with each other within the scope of technical compatibility.

[0065] (Modifications of the Overall Configuration) The electronic component 10 is not limited to a negative temperature coefficient thermistor component. For example, the electronic component 10 may be a thermistor component other than a negative temperature coefficient thermistor component, a multilayer capacitor component, or an inductor component, as long as it has some kind of wiring inside the element body 20.

[0066] The material of the element body 20 is not limited to the example of the above embodiment. For example, the material of the element body 20 may be a composite of resin and metal powder, fiber, thermosetting resin, or other material. 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 columnar shape other than a quadrangular columnar shape having a central axis CA. The element body 20 may also be the core of a wire-wound 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 at each end of the winding core portion.

[0067] The boundary portion between adjacent flat surfaces on the outer surface 21 of the element body 20 does not have to be chamfered. In this case, there is no curved surface at the boundary portion. The shapes of the first internal electrodes 41 and second internal electrodes 42 are not important as long as they ensure electrical conduction with the corresponding first external electrodes 61 and second external electrodes 62. Furthermore, 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.

[0068] 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. The same applies to the second external electrode 62.

[0069] The materials of the first internal electrode 41, the second internal electrode 42, the first external electrode 61, and the second external electrode 62 are not important. Any material may be used as long as electrical conduction between the first internal electrode 41 and the second internal electrode 42 and the corresponding first external electrode 61 and the second external electrode 62 is ensured. For example, the materials of the first internal electrode 41 and the second internal electrode 42 may be conductive materials such as silver or copper. Furthermore, the materials of the first external electrode 61 and the second external electrode 62 do not have to be resin electrodes. For example, they may be electrodes made of a mixture of silver and glass that does not contain resin. Furthermore, the material of the conductive filler mixed with the resin in the first external electrode 61 and the second external electrode 62 is not limited to silver. For example, it may be copper.

[0070] 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.

[0071] The configuration of the glass film 51 is not limited to the example in the above embodiment. For example, the area covered by the glass film 51 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.

[0072] In the portion of glass film 51 that is covered with first base electrode 61A, the glass contained in glass film 51 may be diffused into the glass of first base electrode 61A. In other words, glass film 51 and the glass contained in first base electrode 61A may be integrated. The same applies to second base electrode 62A.

[0073] The organosilane compound is not limited to GPTMS. The organosilane compound does not necessarily have to have any of an epoxy group, a mercapto group, an amino group, a vinyl group, or a methacryl group. For example, the organosilane compound may be 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, (3-glycidoxypropyl)methyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, or n-decyltrimethoxysilane. The organosilane compound does not necessarily have to have a carbon chain with three or more carbon atoms. The presence of an organic silane compound in the glass film 51 can be determined by using methods such as X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, Raman spectroscopy, and energy dispersive X-ray analysis.

[0074] Filling portion 52 does not have to fill gap 23 closest to geometric center GC of element body 20. In other words, filling portion 52 only needs to fill at least a portion of gap 23 in element body 20. Furthermore, electronic component 10 does not need to have filling portion 52, and only needs to include at least glass film 51.

[0075] (Modifications of the recess and the glass film covering the recess) The maximum depth H of the recess 24 may be smaller than 0.3 μm or larger than 3 μm. Even in these cases, the effect described in (1) can be obtained as long as the arithmetic mean roughness of the portion of the outer surface 53 of the glass film 51 covering the recess 24 is 3 nm or more and 200 nm or less.

[0076] The maximum dimension L of the line segment LS connecting two points on the opening edge 25 of the recess 24 may be smaller than 0.5 μm or larger than 20 μm. Even in these cases, the effect described in (1) can be obtained.

[0077] The arithmetic mean roughness of outer surface 53 of glass film 51 at the portion covering flat surface 26 does not have to be smaller than the arithmetic mean roughness of outer surface 53 of glass film 51 at the portion covering recess 24. As long as the arithmetic mean roughness of outer surface 53 of glass film 51 at least at the portion covering recess 24 is 3 nm or more and 200 nm or less, the effect described in (1) can be obtained.

[0078] The average value of thickness T2 of glass film 51 at the portion covering flat surface 26 may be smaller than 15 nm or larger than 1000 nm. Even in such a case where thickness T2 of glass film 51 is smaller than 15 nm, the effect described in (1) can be obtained as long as the arithmetic mean roughness of glass film 51 covering recess 24 is within a predetermined range.

[0079] (Modification of the Manufacturing Method) The solvent 82 introduced in the solvent introduction step S13 is not limited to the example in the above embodiment, and may be any liquid that can disperse the metal alkoxide appropriately.

[0080] The solvent introduction step S13 may be performed after the catalyst introduction step S14 or the matrix introduction step S15. The solvent introduction step S13 may be performed before at least one of the solution introduction step S16 and the catalyst introduction step S14. The solvent introduction step S13 may also be omitted. In this case, for example, if the amount of water contained in the catalyst-containing aqueous solution 83 is appropriately large, the metal alkoxide will react in the liquid phase. The catalyst-containing aqueous solution 83 may also be introduced in a state where it is mixed with an organic solvent as the solvent 82.

[0081] Although the catalyst-containing aqueous solution 83 is ammonia water and the catalyst is hydroxide ions, the catalyst is not limited to this. A basic aqueous solution can promote the hydrolysis of metal alkoxide as a catalyst, similar to the ammonia water in the above embodiment. Even an acidic aqueous solution can promote the hydrolysis of metal alkoxide as a catalyst. Furthermore, even a neutral aqueous solution can be used as long as it contains a substance that functions as a catalyst, such as ions that can promote hydrolysis.

[0082] Although the catalyst has been described as being introduced as an aqueous solution 83 containing the catalyst, a solid compound containing the catalyst and water may be introduced separately into the reaction vessel 81. In this case, the catalyst can be considered to have been introduced into the reaction vessel 81 when it is produced in the reaction vessel 81. Also, for example, a solid compound containing the catalyst may be introduced into the reaction vessel 81, and moisture in the air may be used as the water required for hydrolysis.

[0083] The raw body introduction step S15 may be performed before the catalyst introduction step S14. Furthermore, if the raw body introduction step S15 is performed before the catalyst introduction step S14, the solution introduction step S16 may be performed before the catalyst introduction step S14 or the raw body introduction step S15. It is sufficient that at least the raw body introduction step S15 is performed before either the solution introduction step S16 or the catalyst introduction step S14.

[0084] In the solution introduction step S16, instead of a metal alkoxide, a solution containing a precursor for generating the metal alkoxide may be introduced. In this case, a metal complex or acetate, which is a metal alkoxide precursor, may be introduced in the solution introduction step S16. Examples of metal complexes 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. Examples of acetates include zirconium acetate, zirconium(IV) hydroxide acetate, and basic aluminum acetate.

[0085] In the solution introduction step S16, the metal alkoxide may be generated outside the reaction vessel 81 and then introduced into the reaction vessel 81, but may also be generated within the reaction vessel 81. For example, the metal alkoxide is generated by the reaction of a metal salt with an alcohol. Therefore, even when a metal salt and an alcohol, which are metal alkoxide precursors, are introduced into the reaction vessel 81 and the metal alkoxide is generated by the reaction between them, the metal alkoxide can be considered to have been introduced into the reaction vessel 81.

[0086] The metal alkoxide is not limited to TEOS. For example, the metal contained in the metal alkoxide may be titanium, zirconium, aluminum, or the like. When the metal contained in the metal alkoxide is silicon, the reaction rate is slower than that of other metals, making it easier to control the reaction rate of the metal alkoxide to a constant value. Furthermore, the alkoxy group of the metal alkoxide may be a methoxy group, a propoxy group, or the like, or may be modified with a functional group such as a long-chain alkyl group or an epoxy group, as in a coupling agent. Furthermore, the coordination number for the metal contained in the metal alkoxide is not limited to tetracoordination, but may be 3-coordination or 2-coordination.

[0087] In the solution introduction step S16, it is not necessary to premix the metal alkoxide and the organic silane compound mixture 84. The metal alkoxide and the organic silane compound may be introduced into the reaction vessel 81 individually in a predetermined ratio.

[0088] In the solution introduction step S16, the weight ratio of the organosilane compound to the metal alkoxide introduced into the reaction vessel 81 is not limited to the example in the above embodiment. As long as the glass film 51 can be formed, the first curing step S19 does not have to be performed after the drying step S18. For example, in the second curing step S22, the glass film 51 may be cured together with the firing of the conductive paste.

[0089] In the internal electrode exposing step S20, the method for removing the glass film 51 is not limited to laser cutting. For example, the first internal electrode 41 and the second internal electrode 42 may be exposed by using methods such as ion milling and polishing.

[0090] In the internal electrode exposure process S20, as long as the first internal electrode 41 and the second internal electrode 42 are electrically conductive to the corresponding first base electrode 61A and second base electrode 62A, respectively, the range of removal of the glass film 51 is not limited to the example of the above embodiment.

[0091] The second curing step S22 is not limited to heating the conductive paste. For example, if the conductive paste is made of a material that is cured by ultraviolet light irradiation, the conductive paste may be cured by ultraviolet light irradiation.

[0092] The material of the conductive paste is not limited to resin as long as electrical conduction between the first internal electrode 41 and the second internal electrode 42 is ensured. <Notes> The technical concepts that can be derived from the above-described embodiment and modified examples are described below.

[0093] [1] An electronic component comprising: an element body; and a glass film covering an outer surface of the element body, wherein the material of the glass film contains an organosilane compound; the outer surface of the element body has a recess that is recessed relative to its surroundings; and the arithmetic mean roughness of the outer surface of the glass film at a portion covering the recess is 3 nm or more and 200 nm or less.

[0094] [2] The electronic component according to [1], wherein the average thickness of the glass film covering the outer surface of the element body excluding the recess is 15 nm or more and 1000 nm or less.

[0095] [3] The electronic component according to [1] or [2], wherein the average thickness of the glass film at the portion covering the recess is greater than the average thickness of the glass film at the portion covering the outer surface of the element body excluding the recess.

[0096] [4] The electronic component according to any one of [1] to [3], wherein the maximum dimension of a line segment connecting two points on the opening edge of the recess is 0.5 μm or more and 20 μm or less.

[0097] [5] The electronic component according to any one of [1] to [4], wherein the maximum depth of the recess is 0.3 μm or more and 3 μm or less.

[0098] REFERENCE SIGNS LIST 10... Electronic component 20... Body 21... Outer surface 24... Recess 25... Opening edge 51... Glass film 53... Outer surface CL... Tangent line LS... Line segment L... Dimension H... Maximum depth T1... Thickness T2... Thickness

Claims

1. An electronic component comprising: an element; and a glass film covering an outer surface of the element; the material of the glass film contains an organosilane compound; the outer surface of the element has a recess that is recessed relative to its surroundings; and the arithmetic mean roughness of the outer surface of the glass film at a portion covering the recess is 3 nm or more and 200 nm or less.

2. The electronic component according to claim 1, wherein the average thickness of the glass film covering the outer surface of the element body excluding the recess is 15 nm or more and 1000 nm or less.

3. An electronic component as described in claim 1 or claim 2, wherein the average thickness of the glass film at the portion covering the recess is greater than the average thickness of the glass film at the portion covering the outer surface of the element body excluding the recess.

4. The electronic component according to any one of claims 1 to 3, wherein the maximum dimension of a line segment connecting two points on the edge of the opening of the recess is 0.5 μm or more and 20 μm or less.

5. An electronic component according to any one of claims 1 to 4, wherein the maximum depth of the recess is 0.3 μm or more and 3 μm or less.

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