Electronic components and methods for manufacturing electronic components

Abstract

An electronic component (10) has an element (20), a protective material (50) covering a portion or all of an outer surface (21) of the element (20), and an outer electrode covering a portion of an outer surface (53) of the protective material (50). The element (20) has multiple spaces (23) on the inside. The protective material (50) is glass containing a silane compound having a C3 or higher carbon chain. The protective material (50) has a packing part (52) packed in at least a portion of the spaces (23) and a film part (51) covering an outer surface (21) of the element (20).

Description

Technical Field

[0001] The present disclosure relates to an electronic component and a method for manufacturing an electronic component.

Background Art

[0002] The electronic component described in Patent Document 1 includes an element body, a protective material covering an outer surface of the element body, and an external electrode covering a part of an outer surface of the protective material. The element body is porous and has voids therein. Patent Document 1 also discloses a glass film as an example of the protective material.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] The glass film serving as the protective material disclosed in Patent Document 1 tends to remain on the outer surface of the element body during the manufacturing process of the glass film. Therefore, it is difficult to fill the voids inside the element body with glass. As a result, voids tend to remain inside the element body, and cracks or the like are likely to occur in the element body starting from the voids.

Means for Solving the Problem

[0005] In order to solve the above problem, one aspect of the present disclosure is an electronic component including: an element body; a protective material covering part or all of an outer surface of the element body; and an external electrode covering a part of an outer surface of the protective material, wherein the element body has a plurality of voids therein, the protective material is glass containing a silane compound having a carbon chain with 3 or more carbon atoms, and the protective material has a filling portion filled in at least a part of the voids, and a film portion covering the outer surface of the element body.

[0006] Furthermore, one aspect of the present disclosure is a method for manufacturing an electronic component, comprising: a body preparation step of preparing a body having a plurality of voids inside; a body introduction step of introducing the body into a reaction vessel; a solution introduction step of introducing a solution containing a metal alkoxide or a metal alkoxide precursor and a silane compound having a carbon chain with 3 or more carbon atoms into the reaction vessel; and a protective material formation step of hydrolyzing and dehydrating the metal alkoxide on the outer surface of the body and forming a protective material consisting of a filling portion that fills the plurality of voids and a film portion that covers the outer surface of the body.

[0007] According to the above configuration, the protective material is glass containing a silane compound. Since this silane compound has carbon chains with three or more carbon atoms, the glass easily penetrates into the voids inside the substrate during the manufacturing process of the protective material. As a result, the protective material has not only a film portion that covers the outer surface of the substrate, but also a filling portion that fills the voids. If the filling portion, which is part of the protective material, fills the voids in the substrate in this way, it is possible to prevent cracks and other damage from occurring in the substrate starting from the voids in the substrate. [Effects of the Invention]

[0008] By filling the voids inside the base body, the strength of the base body can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of an electronic component. [Figure 2] This is a side view of an electronic component. [Figure 3] This is a cross-sectional view along line 3-3 in Figure 2. [Figure 4] This is a magnified cross-sectional view of the vicinity of the film portion of an electronic component. [Figure 5] This is an explanatory diagram illustrating the manufacturing method of electronic components. [Figure 6] This is an explanatory diagram illustrating the manufacturing method of electronic components. [Figure 7] This is an explanatory diagram illustrating the manufacturing method of electronic components. [Figure 8]This is an explanatory diagram illustrating the manufacturing method of electronic components. [Figure 9] This is an explanatory diagram illustrating the manufacturing method of electronic components. [Modes for carrying out the invention]

[0010] <An embodiment of an electronic component> An embodiment of an electronic component will be described below with reference to the drawings. Note that the drawings may show components enlarged for ease of understanding. The dimensional ratios of the components may differ from those in the actual components or those shown in other drawings.

[0011] (Regarding the overall structure) As shown in Figure 1, the electronic component 10 is, for example, a surface-mount type negative-resistance thermistor component that is mounted on a circuit board or the like. A negative-resistance thermistor component has the characteristic that its resistance decreases as the temperature rises.

[0012] The electronic component 10 comprises a base body 20. The base body 20 is roughly rectangular in shape and has a central axis CA. In the following, the axis extending along the central axis CA will be referred to as the first axis X. One of the axes perpendicular to the first axis X will be referred to as the second axis Y. The axis perpendicular to both the first axis X and the second axis Y will be referred to as the third axis Z. Furthermore, one direction along the first axis X will be referred to as the first positive direction X1, and the direction along the first axis X opposite to the first positive direction X1 will be referred to as the first negative direction X2. Furthermore, one direction along the second axis Y will be referred to as the second positive direction Y1, and the direction along the second axis Y opposite to the second positive direction Y1 will be referred to as the second negative direction Y2. Furthermore, one direction along the third axis Z will be referred to as the third positive direction Z1, and the direction along the third axis Z opposite to the third positive direction Z1 will be referred to as the third negative direction Z2.

[0013] The outer surface 21 of the base body 20 has six planes 22. Here, "planes" of the base body 20 refer to surfaces that can be observed as planes when the entire base body 20 is observed. In other words, even if there are minute irregularities or steps that can only be seen by magnifying a part of the base body 20 with a microscope, they are described as planes or curved surfaces. The six planes 22 face in different directions from each other. The six planes 22 can be broadly 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 the face facing the third positive direction Z1, the face facing the third negative direction Z2, the face facing the second positive direction Y1, and the face facing the second negative direction Y2, respectively.

[0014] On the outer surface 21 of the base body 20, the boundary portions of two adjacent planes 22 and the boundary portions of three adjacent surfaces are curved. In other words, the corners of the base body 20 have a rounded chamfer shape. Note that in Figures 1 and 2, the outer surface 53 of the film portion 51 of the protective material 50, which will be described later, is treated as the same as the outer surface 21 of the base body 20 and is denoted accordingly.

[0015] As shown in Figure 2, the dimension of the base body 20 in the direction along the first axis X is larger than the dimension in the direction along the third axis Z. Also, as shown in Figure 3, the dimension of the base body 20 in the direction along the first axis X is larger than the dimension in the direction along the second axis Y. The material of the base body 20 is a ceramic obtained by firing a metal oxide composed of one or more elements selected from Mn, Fe, Ni, Co, Ti, Ba, Al, and Zn. Therefore, as shown in Figure 4, the base body 20 has multiple voids 23 inside. These voids 23 are mainly located at the boundaries of the particles that make up the sintered base body 20. Note that the illustration of the voids 23 is omitted in Figure 3.

[0016] Here, the ratio of the total volume of the voids 23 to the volume of the base body 20 is defined as the void ratio. The volume of the base body 20 includes the volume of the voids 23 in addition to the volume of the ceramic portion. When defined in this manner, the void ratio is 0.5% or more and 2.5% or less. The method for calculating the void ratio is as follows. First, an image of a 10 µm square region in an arbitrary cross-section of the base body 20 is captured using an electron microscope. Then, similar regions are captured in a plurality of cross-sections, and the integrated value of the area of the voids 23 and the integrated value of the area of the 10 µm square imaging regions in the plurality of captured images are obtained. The void ratio is obtained by multiplying "the integrated value of the area of the voids 23 / the integrated value of the area of the imaging regions" by 100. Therefore, in the present embodiment, the void ratio is expressed as a percentage.

[0017] As shown in Figure 3, the electronic component 10 includes two first internal electrodes 41 and two second internal electrodes 42. Both the first internal electrodes 41 and the second internal electrodes 42 are embedded inside the base body 20.

[0018] The material of the first internal electrodes 41 is a conductive material. For example, the material of the first internal electrodes 41 is palladium. Further, the material of the second internal electrodes 42 is the same as the material of the first internal electrodes 41.

[0019] The shape of the first internal electrodes 41 is a rectangular plate shape. The main surface of the first internal electrodes 41 is orthogonal to the second axis Y. The shape of the second internal electrodes 42 is the same rectangular plate shape as that of the first internal electrodes 41. Similar to the first internal electrodes 41, the main surface of the second internal electrodes 42 is orthogonal to the second axis Y.

[0020] The dimension of the first internal electrode 41 along the first axis X is smaller than the dimension of the base body 20 along the first axis X. Further, as shown in Figure 1, the dimension of the first internal electrode 41 along the third axis Z is approximately two-thirds of the dimension of the base body 20 along the third axis Z. The dimensions of the second internal electrode 42 in each direction are the same as the dimensions of the first internal electrode 41.

[0021] As shown in Figure 3, the first internal electrode 41 and the second internal electrode 42 are positioned alternately along the second axis Y. That is, they are arranged in the order of first internal electrode 41, second internal electrode 42, first internal electrode 41, second internal electrode 42, from the side surface 22C facing the second positive direction Y1 toward the second negative direction Y2. In this embodiment, the distance between each internal electrode along the second axis Y is equal.

[0022] As shown in Figure 1, the two first internal electrodes 41 and the two second internal electrodes 42 are all located in the center of the body 20 in the direction along the third axis Z. On the other hand, as shown in Figure 3, the first internal electrodes 41 are located towards the first positive direction X1, and the second internal electrodes 42 are located towards the first negative direction X2.

[0023] Specifically, the first positive X1 end of the first internal electrode 41 coincides with the first positive X1 end of the base body 20. In other words, the first positive X1 end of the first internal electrode 41 is exposed on the first end face 22A of the base body 20. The first negative X2 end of the first internal electrode 41 is located inside the base body 20 and does not reach the first negative X2 end of the base body 20. On the other hand, the first negative X2 end of the second internal electrode 42 coincides with the first negative X2 end of the base body 20. In other words, the first negative X2 end of the first internal electrode 41 is exposed on the second end face 22B of the base body 20. The first positive X1 end of the second internal electrode 42 is located inside the base body 20 and does not reach the first positive X1 end of the base body 20.

[0024] As shown in Figure 4, the electronic component 10 is equipped with a protective material 50. The protective material 50 is an insulating glass. The glass contained in the protective material 50 contains silicon dioxide and a silane compound having a carbon chain with 3 or more carbon atoms. The silane compound that forms the material of the protective material 50 has one or more functional groups selected from epoxy groups, mercapto groups, amino groups, vinyl groups, and methacrylic groups. Specifically, the silane compound is 3-glycidoxypropyltrimethoxysilane (hereinafter referred to as "GPTMS"). Note that GPTMS has an epoxy group as a functional group.

[0025] As shown in Figure 3, the electronic component 10 includes a first external electrode 61 and a second external electrode 62. In Figures 1 to 3, the first external electrode 61 and the second external electrode 62 are shown by dashed lines.

[0026] The first external electrode 61 comprises 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 base body 20, including the first end face 22A. Specifically, the first base electrode 61A covers the first end face 22A of the base body 20 and also covers a portion of the first positive direction X1 side of the four side surfaces 22C from above the protective material 50. That is, 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, it is a mixture of organic resin and silver particles.

[0027] 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 in the diagram, the first metal layer 61B has a two-layer structure consisting of a nickel layer and a tin layer, in that order from the side of the first base electrode 61A. 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 base body 20, including the second end face 22B. Specifically, the second base electrode 62A covers the second end face 22B of the base body 20 and also covers a portion of the first negative direction X2 side of the four side surfaces 22C from above the protective material 50. That is, the second base electrode 62A is a five-sided electrode. In this embodiment, the material of the second base electrode 62A is the same as the material of the first external electrode 61, and is a resin electrode. More specifically, it is a mixture of organic resin and silver particles.

[0029] The second metal layer 62B covers the second base electrode 62A from the outside. Therefore, the second metal layer 62B is laminated on the second base electrode 62A. Specifically, the second metal layer 62B has a two-layer structure consisting of nickel plating and tin plating, similar to the first metal layer 61B. 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 extend to the first external electrode 61 on the side surface 22C, and is positioned separately from the first external electrode 61 in a direction along the first axis X. Furthermore, on the side surface 22C of the base body 20, the central portion in the direction along the first axis X is not laminated with the first external electrode 61 and the second external electrode 62, and the film portion 51 of the protective material 50 is exposed.

[0031] (Regarding protective materials) As shown in Figure 4, the protective material 50 has a membrane portion 51 and a filling portion 52. The membrane portion 51 covers part or all of the outer surface 21 of the base body 20. Specifically, the membrane portion 51 covers all four sides 22C of the outer surface 21 of the base body 20. The filling portion 52 fills at least some of the voids 23.

[0032] The average thickness T of the film portion 51 is between 20 nm and 1000 nm. The average thickness T of the film portion 51 is calculated as follows: First, a cross-section of the element 20 is imaged using an electron microscope. For this image, a measurement range of at least 10 μm is defined along the outer surface 53 of the film portion 51. Then, the cross-sectional area of ​​the film portion 51 in this measurement range is calculated by image processing. Finally, the average thickness T of the film portion 51 in the measurement range is calculated by dividing this cross-sectional area by the length of the measurement range along the outer surface 53 of the film portion 51.

[0033] Furthermore, the arithmetic mean roughness of the outer surface 53 of the film portion 51 is between 6 nm and 100 nm. The arithmetic mean roughness of the outer surface 53 of the film portion 51 is calculated as follows. First, areas without depressions caused by the detachment of ceramic particles, cracks, or chips in the substrate 20 are identified. Specifically, these areas are identified as follows: First, the substrate 20 is cut in a direction perpendicular to the outer surface 21 of the substrate 20 by focused ion beam processing or the like. Then, the cross-section of the cut area is imaged using an electron microscope or the like. In the imaged cut cross-section, tangent lines are drawn that circumscribe both sides of the outer surface 21 that enclose the depression. Note that a portion of the tangent line may coincide with the outer surface 21 of the substrate 20. At this time, the length from the tangent line to the inner surface of the depression in a direction perpendicular to the tangent line is defined as the depth of the depression in that cut cross-section. Next, the substrate 20 is further cut by a predetermined imaging pitch in a direction perpendicular to the cut cross-section, and a new cut cross-section is imaged. That is, a new cut cross-section of the substrate 20 that is approximately parallel to the cut cross-section is imaged. Then, the depth of the depression in this new cut cross-section is measured in the same manner. In this manner, the process of photographing the cut cross-section of the base body 20 and measuring the depth of the recesses is repeated. The largest value among the recess depths obtained in each cut cross-section is taken as the maximum depth of the entire recess. If the maximum depth of the recess is 10 times or more the arithmetic mean roughness of the entire outer surface 21 of the base body 20, the recess is designated as a "recess caused by the shedding of ceramic particles, cracks and chips in the base body 20, etc."

[0034] Next, in areas where there are no "depressions caused by the detachment of ceramic particles, cracks and chips in the base body 20, etc.," the measurement range is defined as an area of ​​at least 10 μm in the direction along the outer surface 53 of the film portion 51. Then, within this measurement range, the arithmetic mean roughness of the outer surface 53 of the film portion 51 is measured by white light interferometry.

[0035] The filling portion 52 fills the void 23 located closest to the geometric center GC of the base body 20. As shown in Figure 3, the geometric center GC of the base body 20 is the center point of the base body 20, including the first internal electrode 41 and the second internal electrode 42 located inside the base body 20. Here, as will be described later, the liquid that will become the material for the glass penetrates from the outer surface 21 of the base body 20 into the interior, thereby forming the filling portion 52. Therefore, if the filling portion 52 fills the void 23 located closest to the geometric center GC of the base body 20, it can be considered that the filling portion 52 fills almost all of the voids 23 in the base body 20.

[0036] Whether the filling portion 52 fills the void 23 located closest to the geometric center GC of the base body 20 can be confirmed by imaging a cross-section of the base body 20 including the geometric center GC using an electron microscope. A slight deviation from the geometric center GC is acceptable due to processing accuracy during the cutting of the base body 20. Even if the deviation is approximately 5% of the dimension of the base body 20 in the direction along the first axis X relative to the geometric center GC in the strict sense, 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 third axis Z.

[0037] As described above, since the filling portion 52 fills almost all of the voids 23 in the base body 20, when the ratio of the total volume of the filling portion 52 to the volume of the base body 20 is defined as the filling rate, the filling rate is approximately the same as the void rate. Therefore, the filling rate is between 0.5% and 2.5%, similar to the void rate. Thus, under the premise that the filling portion 52 fills almost all of the voids 23 in the base body 20, the void rate can also be indirectly measured by measuring the filling rate.

[0038] The method for calculating the packing efficiency is the same as the method for calculating the void ratio. First, an electron microscope is used to image a 10 μm square area in any cross-section of the substrate 20. Then, the same area is imaged in multiple cross-sections, and the cumulative value of the area of ​​the packing portion 52 and the cumulative value of the area of ​​the 10 μm square imaging area are determined for the multiple images obtained. The packing efficiency is then calculated by multiplying "cumulative value of the area of ​​the packing portion 52 / cumulative value of the area of ​​the imaging area" by 100. Therefore, in this embodiment, the packing efficiency is expressed as a percentage.

[0039] (Regarding the manufacturing methods of electronic components) Next, we will describe the manufacturing method of the electronic component 10. As shown in Figure 5, the manufacturing method for the electronic component 10 further comprises a base material preparation step S11, an R-chamfering step S12, a solvent input step S13, a catalyst input step S14, a base material input step S15, a solution input step S16, a protective material formation step S17, an internal electrode exposure step S18, a conductor coating step S19, a conductor hardening step S20, and a plating step S21.

[0040] First, the base body preparation step S11 is performed. In the base body preparation step S11, a rectangular parallelepiped base body 20 having six planes 22 is prepared. That is, at this stage, the base body 20 is in the state before R chamfering. For example, first, several ceramic sheets that will become the base body 20 are prepared. These sheets are thin plates. A conductive paste that will become the first internal electrode 41 is laminated onto these sheets. On top of the laminated paste, a ceramic sheet that will become the base body 20 is laminated. On top of the laminated paste, a conductive paste that will become the second internal electrode 42 is laminated. In this way, the ceramic sheets and conductive paste are laminated. Then, by cutting to a predetermined size, an unfired laminated base body 20 is formed. After that, the base body 20 is prepared by firing this unfired base body 20 at a high temperature. Note that the ceramic sheets have multiple voids inside. Therefore, the prepared base body 20 has multiple voids 23 inside.

[0041] Next, as shown in Figure 5, the R-chamfering process S12 is performed. In the R-chamfering process S12, curved surfaces are formed at the boundaries of two adjacent planes 22 and at the boundaries of three adjacent planes 22 of the base body 20 prepared in the base body preparation process S11. For example, the corners of the base body 20 are R-chamfered by barrel polishing, thereby forming the curved surfaces at the aforementioned boundaries.

[0042] Next, as shown in Figure 5, the solvent addition step S13 is performed. As shown in Figure 6, in the solvent addition step S13, 2-propanol is added to the reaction vessel 81 as the solvent 82. Next, as shown in Figure 5, the catalyst addition step S14 is performed. As shown in Figure 7, in the catalyst addition step S14, stirring of the solvent 82 in the reaction vessel 81 is started first. Then, aqueous ammonia water is added to the reaction vessel 81 as an aqueous solution 83 containing the catalyst. The catalyst in this embodiment is hydroxide ions and functions as a catalyst that promotes the hydrolysis of the metal alkoxide 84, which will be described later.

[0043] Next, as shown in Figure 5, the raw material input step S15 is performed. As shown in Figure 8, in the raw material input step S15, a plurality of raw materials 20 that were previously formed in the R-chamfering step S12 as described above are added to the reaction vessel 81.

[0044] Next, as shown in Figure 5, the solution addition step S16 is performed. As shown in Figure 9, in the solution addition step S16, the metal alkoxide 84 and the silane compound 85 are added to the reaction vessel 81. The metal alkoxide 84 is liquid tetraethyl orthosilicate (hereinafter referred to as "TEOS"). Note that TEOS is sometimes called tetraethoxysilane. The silane compound 85 is liquid GPTMS. The GPTMS is added to TEOS in a weight ratio of 0.12 or more and less than 1. Specifically, the GPTMS is added to TEOS in a weight ratio of approximately 0.43.

[0045] Furthermore, in this embodiment, the amount of solution containing the metal alkoxide 84 and the silane compound 85 to be added in the solution addition step S16 is calculated based on the porosity of the substrate 20 and the area of ​​the outer surface 21 of the substrate 20 added in the substrate addition step S15. Specifically, first, for each substrate 20, the sum of the amount of solution required to fill the voids 23 of the substrate 20 and the amount of solution required to form a film portion 51 covering the outer surface 21 of the substrate 20 is calculated. By multiplying this sum by the number of substrates 20 added in the substrate addition step S15, the required amount of metal alkoxide 84 and silane compound 85 is calculated.

[0046] Next, as shown in Figure 5, the protective material formation process S17 is performed. In the protective material formation process S17, a protective material 50 is formed, consisting of a filling portion 52 that fills a plurality of voids 23 and a film portion 51 that covers the outer surface 21 of the base body 20. The protective material formation process S17 can be further divided into a filling and film formation process S17a, a drying process S17b, and a film hardening process S17c.

[0047] First, the filling and film formation process S17a is performed. In the filling and film formation process S17a, the metal alkoxide 84 and the silane compound 85 are first added to the reaction vessel 81 by the solution addition process S16, and then the stirring of the solvent 82, which was started in the solvent addition process S13 described above, is continued for a predetermined time. As a result, the metal alkoxide 84 is hydrolyzed by hydroxide ions, which act as a catalyst. Then, the condensation polymerization reaction between the metal alkoxides 84 proceeds more slowly than when the silane compound 85 is not present. In other words, the particles of metal alkoxide 84 produced by the condensation polymerization reaction remain small in volume per molecule for a relatively long period of time. Therefore, the metal alkoxide 84 attached to the outer surface 21 of the substrate 20 penetrates into the voids 23 inside the substrate 20 along with the solution. Subsequently, the condensation polymerization reaction of the metal alkoxide 84 proceeds within the voids 23, and the particles of metal alkoxide 84 grow larger. As a result, a filled portion 52 is formed within the voids 23. On the other hand, when the metal alkoxide 84 undergoes hydrolysis, the hydrolyzed metal alkoxide 84 and silane compound 85 adhere to the outer surface 21 of the substrate 20. Then, the metal alkoxide 84 attached to the outer surface 21 of the substrate 20 undergo condensation polymerization to form a film portion 51. Therefore, in the filling and film formation process S17a, a protective material 50 consisting of a sol-like film portion 51 and a sol-like filling portion 52 is formed by a liquid-phase reaction in the reaction vessel 81.

[0048] Next, the drying process S17b is performed. In the drying process S17b, after the filling and film formation process S17a, the substrate 20 is removed from the reaction vessel 81 and dried. As a result, the sol-like protective material 50 is dried and becomes a protective material 50 consisting of a gel-like film portion 51 and a gel-like filling portion 52.

[0049] Next, the film hardening process S17c is performed. In the film hardening process S17c, the base body 20, which has a gel-like protective material 50 formed by the drying process S17b, is fired at a temperature of 140°C to 160°C. Specifically, it is fired at a temperature of 150°C. This hardens the gel-like film portion 51 and the gel-like filling portion 52. In other words, the entire protective material 50, which was in a gel-like state, hardens. At this stage, the film portion 51 of the protective material 50 covers the entire outer surface 21 of the base body 20.

[0050] Next, the internal electrode exposure process S18 is performed. In the internal electrode exposure process S18, the film portion 51 covering the first end face 22A and the second end face 22B of the base body 20 is removed to expose the first internal electrode 41 and the second internal electrode 42. In this embodiment, the film portion 51 is removed by laser cutting over the entire area of ​​the first end face 22A and the entire area of ​​the second end face 22B of the base body 20.

[0051] Next, the conductive coating process S19 is performed. In the conductive coating process S19, conductive paste is applied to a portion of the outer surface 21 of the base body 20 and a portion of the outer surface 53 of the film portion 51. Specifically, conductive paste is applied to two locations: the film portion 51 that covers the first end face 22A of the base body 20 and a portion of the first positive direction X1 side of the four side surfaces 22C of the base body 20, and the film portion 51 that covers the second end face 22B of the base body 20 and a portion of the first negative direction X2 side of the four side surfaces 22C of the base body 20. In this embodiment, the conductive paste contains silver particles and an organic resin.

[0052] Next, the conductive paste curing process S20 is performed. In the conductive paste curing process S20, the conductive paste is cured by heating the substrate 20 to which the conductive paste has been applied. In this embodiment, it is heated to approximately 200 degrees Celsius. The conductive paste applied in the conductive paste coating process S19 is fired to form the first base electrode 61A and the second base electrode 62A.

[0053] Next, the plating process S21 is performed. In the plating process S21, a first metal layer 61B is formed on the surface of the first base electrode 61A by electroplating. Also, a second metal layer 62B is formed on the surface of the second base electrode 62A. Although not shown in the diagram, 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 way, the electronic component 10 is formed.

[0054] (Regarding the effects of this embodiment) (1) According to the above configuration, the protective material 50 is glass containing a silane compound. Since this silane compound has carbon chains with 3 or more carbon atoms, the glass easily enters the voids 23 inside the base body 20 during the manufacturing process of the protective material 50. As a result, the protective material 50 has not only a film portion 51 that covers the outer surface 21 of the base body 20, but also a filling portion 52 that fills the voids 23. In this way, if the filling portion 52, which is part of the protective material 50, fills the voids 23 of the base body 20, it is possible to prevent cracks and the like from occurring in the base body 20 starting from the voids 23 in the base body 20.

[0055] (2) In the above embodiment, the thickness T of the film portion 51 is 20 nm or more and 1000 nm or less. If the thickness T of the film portion 51 is less than 20 nm, there is a risk that the adhesion between the film portion 51 and the first external electrode 61 and the second external electrode 62 will be insufficient. On the other hand, if the thickness T of the film portion 51 is greater than 1000 nm, when firing the film portion 51, the temperature difference between the outer surface 53 of the film portion 51 and the surface of the film portion 51 facing the base body 20 may become large. As a result, there may be a difference in the degree of firing between the outer surface 53 of the film portion 51 and the surface of the film portion 51 facing the base body 20. Therefore, if the thickness T of the film portion 51 is 20 nm or more and 1000 nm or less, sufficient adhesion between the first external electrode 61 and the second external electrode 62 can be obtained, and uniform firing is also easier.

[0056] (3) In the above embodiment, the void ratio is 0.5% or more and 2.5% or less. With a void ratio of this magnitude, in the manufacturing method of the above embodiment, almost all of the voids 23 can be filled with the filling portion 52 of the protective material 50. Therefore, no special processes or special manufacturing equipment are required to form the filling portion 52 that fills the voids 23.

[0057] (4) In the above embodiment, the arithmetic mean roughness of the outer surface 53 of the film portion 51 is 6 nm or more and 100 nm or less. If the arithmetic mean roughness of the outer surface 53 of the film portion 51 is less than 6 nm, an anchoring effect is unlikely to occur between the film portion 51 and the first external electrode 61 and the second external electrode 62, and sufficient adhesion may not be obtained. On the other hand, if the arithmetic mean roughness of the outer surface 53 of the film portion 51 is greater than 100 nm, frictional force is likely to occur on the outer surface 53 of the film portion 51, and damage due to friction may occur. Therefore, if the arithmetic mean roughness of the outer surface 53 of the film portion 51 is 6 nm or more and 100 nm or less, sufficient adhesion can be obtained and damage due to friction is unlikely to occur.

[0058] (5) In the above embodiment, the filling portion 52 fills the void 23 located closest to the geometric center GC of the base body 20. That is, the protective material 50 can be considered to have filled almost all of the void 23 of the base body 20. If the void 23 is sufficiently filled in this way, the effect of improving the strength of the base body 20 can be reliably obtained.

[0059] (6) According to the above embodiment, the method for manufacturing the electronic component 10 comprises a solution addition step S16 and a protective material formation step S17. By adding a metal alkoxide 84 and a silane compound 85 having a carbon chain with 3 or more carbon atoms, a film portion 51 and a filled portion 52 can be formed. Therefore, the strength of the base body 20 can be improved without making significant changes to existing manufacturing methods.

[0060] (7) According to the above embodiment, in the solution addition step S16 or the protective material formation step S17, the silane compound 85 has one or more functional groups selected from epoxy groups, mercapto groups, amino groups, vinyl groups, and methacrylic groups. Silane compounds 85 having these functional groups are relatively easy to obtain and easy to produce. Therefore, manufacturing is easy.

[0061] (8) According to the above embodiment, in the solution addition step S16, GPTMS is added to the reaction vessel 81 in a weight ratio of 0.12 or more and less than 1 relative to TEOS. By adding GPTMS in the above ratio relative to TEOS, the protective material 50 can be easily formed while sufficiently reducing the rate of the condensation polymerization reaction of TEOS.

[0062] (9) According to the above embodiment, the method for manufacturing the electronic component 10 comprises a conductive coating step S19 and a conductive curing step S20. The conductive paste contains resin as a material. Therefore, the first external electrode 61 and the second external electrode 62 contain resin. That is, the first external electrode 61 and the second external electrode 62 are resin electrodes. Resin electrodes can be fired at a lower temperature compared to metal electrodes made of silver or the like. Therefore, the energy cost required for firing can be reduced. In addition, since the material of the protective material 50 is a so-called organic-inorganic hybrid, high adhesion of each external electrode to the film portion 51 can be obtained.

[0063] (10) According to the above embodiment, the filling portion 52 and the film portion 51 can be formed by firing at a temperature of 140 degrees Celsius or more and 160 degrees Celsius or less. This allows the use of a material with lower heat resistance than ceramics or the like as the material for the base body 20. Therefore, the selectivity of the material for the base body 20 is increased. In addition, the energy cost required for firing can be reduced.

[0064] <Example of changes> The above embodiments and the following modifications can be combined and implemented to the extent that they do not conflict with each other technically.

[0065] • The electronic component 10 is not limited to a negative-characteristic thermistor component. For example, if the base body 20 has some kind of wiring inside, it may be a thermistor component other than a negative-characteristic one, or it may be a multilayer capacitor component or an inductor component.

[0066] The material of the base body 20 is not limited to the examples of the embodiments described above. Furthermore, the material of the base body 20 is not limited to a sintered body, as long as it has internal voids. For example, the material of the base body 20 may be a composite body of resin and metal powder, fiber, thermosetting resin, or the like.

[0067] The shape of the base body 20 is not limited to the examples of the above embodiments. For example, the base body 20 may be a polygonal columnar shape other than a rectangular columnar shape having a central axis CA. The base body 20 may also be the core of a wound-type inductor component. For example, the core may be 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.

[0068] The boundary portion of adjacent planes 22 on the outer surface 21 of the base body 20 does not necessarily have to be chamfered. In this case, there is no curved surface at the boundary portion. The shapes of the first internal electrode 41 and the second internal electrode 42 are not limited as long as they can ensure electrical conductivity with the corresponding first external electrode 61 and the second external electrode 62. Also, there is no limit to the number of first internal electrodes 41 and second internal electrodes 42; there may be one internal electrode or three or more.

[0069] The configuration of the first external electrode 61 is not limited to the examples of the above embodiment. For example, the first external electrode 61 may consist only of the first base electrode 61A, and the first metal layer 61B may not have a two-layer structure. The same applies to the second external electrode 62.

[0070] 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 limited. It is sufficient to ensure electrical conductivity between the first internal electrode 41 and the second internal electrode 42 and the corresponding first external electrode 61 and second external electrode 62. 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. Also, 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.

[0071] The placement 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 placed only on the first end face 22A and one side face 22C. The same applies to the second external electrode 62.

[0072] The protective material 50 does not need to cover all areas of the outer surface 21 of the base body 20. The area covered by the protective material 50 can be appropriately changed according to the shape of the base body 20, the positions of the first external electrode 61 and the second external electrode 62, etc.

[0073] Regarding the portion of the protective material 50 that is covered by the first base electrode 61A, the glass contained in the protective material 50 may be diffused into the glass of the first base electrode 61A. In other words, the protective material 50 and the glass contained in the first base electrode 61A may be integrated. The same applies to the second base electrode 62A.

[0074] The average thickness T of the film portion 51 may be less than 20 nm or greater than 1000 nm. Regardless of the thickness T, the presence of the protective material 50 improves the strength of the base body 20 compared to when they are not present.

[0075] The arithmetic mean roughness of the outer surface 53 of the film portion 51 may be less than 6 nm or greater than 100 nm. The arithmetic mean roughness of the outer surface 53 of the film portion 51 can be appropriately changed depending on the dimensions of the electronic component 10, the required strength of the electronic component 10, etc.

[0076] When measuring the arithmetic mean roughness of the outer surface 53 of the film portion 51 and the arithmetic mean roughness of the outer surface 21 of the element 20, instruments such as a laser microscope, atomic force microscope, or stylus profiling system may be used instead of white light interferometry.

[0077] The filling portion 52 does not have to fill the void 23 at the position closest to the geometric center GC of the base body 20. In other words, the filling portion 52 only needs to fill at least a portion of the void 23 of the base body 20.

[0078] The filling rate may be less than 0.5% or greater than 2.5%. In other words, assuming that the filling portion 52 fills almost all of the voids 23, the void ratio may be less than 0.5% or greater than 2.5%. Even if the void ratio is small, if the filling portion 52 fills the voids 23, the effect of (1) can be obtained to some extent. Also, even if the void ratio is large, depending on the conditions of the solution injection step S16 and the protective material formation step S17, it may be possible to fill all of the voids 23 with the filling portion 52.

[0079] The solvent 82 added in the solvent addition step S13 is not limited to the example of the above embodiment, and any liquid that can adequately disperse the metal alkoxide 84 is acceptable. The solvent addition step S13 may be performed after the catalyst addition step S14 or the element addition step S15. The solvent addition step S13 may be performed before at least one of the solution addition step S16 and the catalyst addition step S14. The solvent addition step S13 may also be omitted. In this case, for example, if the amount of water in the aqueous solution 83 containing the catalyst is sufficiently large, the metal alkoxide 84 will react in the liquid phase. Alternatively, the aqueous solution 83 containing the catalyst may be added in a state mixed with the organic solvent 82.

[0080] The aqueous solution 83 containing the catalyst is aqueous ammonia, and the catalyst is hydroxide ions, but the catalyst is not limited to this. Any basic aqueous solution can promote the hydrolysis of metal alkoxide 84 as a catalyst, similar to the aqueous ammonia in the above embodiment. Even an acidic aqueous solution can promote the hydrolysis of metal alkoxide 84 as a catalyst. Furthermore, even a neutral aqueous solution is acceptable as long as it contains a substance that functions as a catalyst, such as ions that can promote hydrolysis.

[0081] Although it has been explained that the catalyst is introduced as an aqueous solution 83 containing the catalyst, the solid compound containing the catalyst and water may be introduced into the reaction vessel 81 separately. In this case, the catalyst can be considered introduced into the reaction vessel 81 because it has been formed inside the reaction vessel 81. Alternatively, for example, the solid compound containing the catalyst may be introduced into the reaction vessel 81, and moisture from the air may be used as the water necessary for hydrolysis.

[0082] The substrate addition step S15 may be performed before the catalyst addition step S14. Also, if the substrate addition step S15 is performed before the catalyst addition step S14, the solution addition step S16 may be performed before the catalyst addition step S14 or the substrate addition step S15. At a minimum, the substrate addition step S15 only needs to be performed before either the solution addition step S16 or the catalyst addition step S14.

[0083] In the method for manufacturing the electronic component 10 of the above embodiment, instead of the metal alkoxide 84, a solution containing a precursor for generating the metal alkoxide 84 may be added. In this case, in the solution addition step S16, a metal complex or acetate, which is a metal alkoxide precursor, may be added. Examples of metal complexes include acetylacetonates such as lithium acetylacetonate, titanium(IV) oxyacetylacetonate, titanium diisopropoxide bis(acetylacetonate), zirconium(IV) trifluoroacetylacetonate, zirconium(IV) acetylacetonate, aluminum acetylacetate, aluminum(III) acetylacetonate, calcium(II) acetylacetonate, and zinc(II) acetylacetonate. Examples of acetates include zirconium acetate, zirconium(IV) hydroxide acetate, and basic aluminum acetate.

[0084] The solution addition step S16 does not require the metal alkoxide 84 to be generated outside the reaction vessel 81 and then added to the reaction vessel 81; instead, the metal alkoxide 84 may be generated inside the reaction vessel 81. For example, metal alkoxide 84 is produced by the reaction of a metal salt and an alcohol. Therefore, even if a metal salt, which is a metal alkoxide precursor, and an alcohol are added to the reaction vessel 81 and react to produce metal alkoxide 84, this can be considered as the metal alkoxide 84 being added to the reaction vessel 81.

[0085] • Metal alkoxide 84 is not limited to TEOS. For example, the metal contained in metal alkoxide 84 may be titanium, zirconium, aluminum, etc. If the metal contained in metal alkoxide 84 is silicon, the reaction rate is slower compared to other metals, making it easier to control the reaction rate of metal alkoxide 84 to a constant level. Furthermore, the alkoxy group of metal alkoxide 84 may be a methoxy group, a propoxy group, etc., or it may be modified with functional groups such as long-chain alkyl groups or epoxy groups, as in a coupling agent. In addition, the coordination number with respect to the metal contained in metal alkoxide 84 is not limited to 4-coordination, but may be 3-coordination or 2-coordination.

[0086] Silane compound 85 is not limited to GPTMS as long as it has a carbon chain with 3 or more carbon atoms. Furthermore, silane compound 85 does not have to have any epoxy group, mercapto group, amino group, vinyl group, or methacrylic group. For example, silane compound 85 may be silane compounds such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, (3-glycidoxypropyl)methyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, and n-decyltrimethoxysilane. Furthermore, in the protective material 50 that has undergone the protective material formation process S17, the presence of the silane compound 85 can be identified by using methods such as X-ray photoelectron spectroscopy, Fourier transform infrared spectrophotometer, Raman spectroscopy, and energy-dispersive X-ray analysis.

[0087] In the solution addition step S16, the order in which the metal alkoxide 84 and the silane compound 85 are added does not matter. Alternatively, a solution in which the metal alkoxide 84 and the silane compound 85 are mixed in a predetermined ratio may be added to the reaction vessel 81 beforehand.

[0088] In the solution addition step S16, the weight ratio of the silane compound 85 to the metal alkoxide 84 added to the reaction vessel 81 may be less than 0.12 or greater than 1. If a protective material 50 can be formed, the strength of the base body 20 can be improved.

[0089] If the protective material 50 can be formed in the protective material formation step S17, the film curing step S17c does not have to be performed after the drying step S17b. For example, the protective material 50 may be cured in conjunction with the firing of the conductive paste in the conductive material curing step S20. In that case, the conductive material curing step S20 and the film curing step S17c are considered to be performed simultaneously.

[0090] In the film hardening step S17c of the protective material formation step S17, the firing temperature of the solution containing the metal alkoxide 84 and silane compound 85 attached to the outer surface 21 of the base body 20 may be lower than 140 degrees or higher than 160 degrees. Even at a high firing temperature, the protective material 50 can be formed if a heat-resistant material such as ceramics is used as the material for the base body 20.

[0091] In the internal electrode exposure step S18, the method for removing the film portion 51 is not limited to laser cutting. For example, the first internal electrode 41 and the second internal electrode 42 may be exposed using methods such as ion milling or polishing.

[0092] In the internal electrode exposure step S18, if the first internal electrode 41 and the second internal electrode 42 and the corresponding first base electrode 61A and second base electrode 62A are electrically conductive, the range over which the film portion 51 is removed is not limited to the example of the above embodiment.

[0093] The conductive curing process S20 is not limited to heating the conductive paste. For example, if a material that is cured by ultraviolet irradiation is used as the conductive paste, ultraviolet irradiation may be performed.

[0094] The material of the conductive paste is not limited to resin, as long as electrical conductivity between the first internal electrode 41 and the second internal electrode 42 can be ensured. When the arithmetic mean roughness of the area where the conductive paste is applied is large, adhesion can be obtained due to the anchoring effect.

[0095] <Note> The technical concepts that can be derived from the above embodiments and modifications are described below. [1] It comprises a base body, a protective material covering part or all of the outer surface of the base body, and an external electrode covering part of the outer surface of the protective material, The aforementioned body has multiple voids inside, The protective material is a glass containing a silane compound having a carbon chain with three or more carbon atoms, and is an electronic component having a filling portion that fills at least some of the voids and a film portion that covers the outer surface of the base body.

[0096] [2] The electronic component described in [1], wherein the average thickness of the film portion is 20 nm or more and 1000 nm or less.

[0097] [3] The electronic component according to [1] or [2], wherein the ratio of the total volume of the filling portion to the volume of the base body is 0.5% or more and 2.5% or less.

[0098] [4] The electronic component according to any one of [1] to [3], wherein the arithmetic mean roughness of the outer surface of the film portion is 6 nm or more and 100 nm or less.

[0099] [5] The external electrode is an electronic component according to any one of [1] to [4], which includes a resin. [6] The protective material fills the gap at the position closest to the geometric center of the element, as described in any one of [1] to [5].

[0100] [7] A body preparation step involves preparing a body having multiple voids inside, A process of introducing the substance into the reaction vessel, A solution addition step involves adding a solution containing a metal alkoxide or a metal alkoxide precursor and a silane compound having a carbon chain with 3 or more carbon atoms to the reaction vessel. A method for manufacturing an electronic component, comprising: a protective material forming step of hydrolyzing and condensing polymerizing the metal alkoxide on the outer surface of the base body, and forming a protective material consisting of a filling portion that fills a plurality of voids and a film portion that covers the outer surface of the base body.

[0101] [8] The method for manufacturing an electronic component according to [7], wherein in the solution input step or the protective material formation step, the silane compound has one or more functional groups selected from epoxy groups, mercapto groups, amino groups, vinyl groups, and methacrylic groups.

[0102] [9] The aforementioned metal alkoxide is tetraethyl orthosilicate. The silane compound is 3-glycidoxypropyltrimethoxysilane, A method for manufacturing an electronic component according to [7] or [8], wherein in the solution addition step, the silane compound is added to the reaction vessel in a weight ratio of 0.12 or more and less than 1 with respect to the metal alkoxide.

[0103]

[10] Following the protective material formation step, a conductive coating step is performed in which a conductive material containing resin is applied to the outer surface of the film portion. A method for manufacturing an electronic component according to any one of [7] to [9], comprising a hardening step of firing the conductor to form an external electrode.

[0104]

[11] A method for manufacturing an electronic component according to any one of [7] to

[10] , wherein in the protective material forming step, the solution containing the metal alkoxide and the silane compound attached to the outer surface of the base body is fired at a temperature of 140 degrees Celsius or more and 160 degrees Celsius or less. [Explanation of symbols]

[0105] 10… Electronic Components 20…body 21…Outer surface 23…gap 50…protective material 51… Membrane section 52…Filling Department 53…Outer surface T…thick

Claims

1. It comprises a base body, a protective material covering part or all of the outer surface of the base body, and an external electrode covering part of the outer surface of the protective material, The aforementioned body has multiple voids inside, The protective material is a glass containing a silane compound having a carbon chain with three or more carbon atoms, and comprises a filling portion that fills at least some of the voids, and a film portion that covers the outer surface of the substrate. Electronic components.

2. The average thickness of the aforementioned film portion is between 20 nm and 1000 nm. The electronic component according to claim 1.

3. The ratio of the total volume of the filling portion to the volume of the base body is 0.5% or more and 2.5% or less. The electronic component according to claim 1.

4. The arithmetic mean roughness of the outer surface of the aforementioned film is between 6 nm and 100 nm. The electronic component according to claim 1.

5. The external electrode includes a resin. The electronic component according to claim 1.

6. The protective material fills the gap at the position closest to the geometric center of the element. The electronic component according to claim 1.

7. A body preparation step involves preparing a body having multiple voids inside, A process of introducing the substance into the reaction vessel, A solution addition step involves adding a solution containing a metal alkoxide or a metal alkoxide precursor and a silane compound having a carbon chain with three or more carbon atoms to the reaction vessel. The process includes a protective material forming step in which the metal alkoxide is hydrolyzed and condensed polymerized on the outer surface of the substrate, and a protective material is formed consisting of a filling portion that fills a plurality of voids and a film portion that covers the outer surface of the substrate. Manufacturing methods for electronic components.

8. In the solution input step or the protective material formation step, the silane compound has one or more functional groups selected from epoxy groups, mercapto groups, amino groups, vinyl groups, and methacrylic groups. A method for manufacturing an electronic component according to claim 7.

9. The aforementioned metal alkoxide is tetraethyl orthosilicate. The silane compound is 3-glycidoxypropyltrimethoxysilane, In the solution addition step, the silane compound is added to the reaction vessel in a weight ratio of 0.12 or more and less than 1 relative to the metal alkoxide. A method for manufacturing an electronic component according to claim 7.

10. Following the protective material formation step, a conductive coating step is performed in which a conductive material containing resin is applied to the outer surface of the film portion. The process includes a hardening step of firing the conductor to form an external electrode. A method for manufacturing an electronic component according to claim 7.

11. In the protective material formation step, the solution containing the metal alkoxide and the silane compound that adheres to the outer surface of the substrate is fired at a temperature of 140°C to 160°C. A method for manufacturing an electronic component according to claim 7.

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