JP6672835B2 - Electronic component manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing an electronic component, and more particularly to a method of manufacturing a multilayer ceramic electronic component such as a multilayer ceramic capacitor.

  In recent years, mobile electronic devices such as mobile phones and portable music players have been reduced in size and thickness. A large number of electronic components, for example, multilayer ceramic electronic components are mounted on a mobile electronic device. With the miniaturization of mobile electronic devices, miniaturization of multilayer ceramic electronic components is also required. In addition, environments in which such mobile electronic devices are used are diversified, and it is desired that multilayer ceramic electronic components have improved reliability in diversified environments.

  Against this background, in an environment where temperature changes are severe, a multilayer ceramic electronic component having a pair of external electrodes has a problem of ion migration. That is, dew condensation occurs on the surface of the multilayer ceramic electronic component due to a difference in temperature or a difference in heat capacity between the multilayer ceramic electronic component and the outside air. The water droplets generated by the condensation form a water film connecting the external electrodes on the surface of the multilayer ceramic electronic component, and when a voltage is applied between the external electrodes of the multilayer ceramic electronic component in that state, the water film is formed on the water film. The ionized metal species is dissolved / precipitated from the external electrode, and ion migration occurs.

  As a method of solving this, for example, there is a method of responding by forming a water-repellent film by silane coupling treatment on the surface of the multilayer ceramic electronic component. In this method, the surface of the multilayer ceramic electronic component is made highly water-repellent by the silane coupling treatment film, and the formation of a water film in a dew condensation environment is suppressed. As one of measures for exhibiting high water repellency by using this silane coupling agent, it is conceivable to lengthen the straight chain of the silane coupling agent.

However, when the straight chain of the silane coupling agent is lengthened, the steric hindrance due to the straight chain increases, so that the distance between the straight chains of the silane coupling treatment film disposed on the surface of the multilayer ceramic electronic component is increased. Inevitably, the denseness is sometimes reduced.
Specifically, the steric hindrance is increased by the length of the linear chain of the silane coupling agent, and the repulsive force is increased. Therefore, the distance between the linear chains is inevitably increased, and the coverage (density) of the electrode portion is increased. Will decrease. As a result, the water generated by the dew condensation easily becomes a water film, and ion migration may occur in the above-described generation process.

  Thus, Patent Document 1 proposes a method of imparting high water repellency by using a perfluoroalkylalkylsilane-based water repellent, that is, a silane coupling agent having F (fluorine) as a functional group. I have. By forming a water-repellent film on the surface of the multilayer ceramic electronic component using this treating agent, continuation of dew condensation is suppressed, and occurrence of ion migration is prevented.

WO 02/082480

  Patent Literature 1 also describes that a silane coupling agent is polymerized by a condensation reaction (crosslinking) between the silane coupling agents in order to increase the denseness of the film. However, in the described embodiment, the condensation reaction is performed. It cannot be controlled, and is mainly a condensation reaction with the laminate, and a condensation reaction between the coupling agents cannot be expected. In addition, a coupling reaction (cross-linking) between the coupling agents can be performed in advance, but also in that case, the reaction cannot be controlled, so that the molecular weight becomes undesirably large, and there is a problem that the coupling agents do not dissolve in the solvent. For this reason, it was difficult to form a highly dense processing film using a silane coupling agent.

  Further, a treatment film formed using a silane coupling agent having F (fluorine) as a functional group disclosed in Patent Document 1 can shorten the linear length of the silane coupling treatment film. Since the distance between the silane coupling agents disposed on the surface of the metal is widened, the coverage (density) between the electrodes is insufficient even in a silane coupling film having F as a functional group, and is sufficient for suppressing ion migration. There is a problem that a special effect cannot be obtained.

  Therefore, a main object of the present invention is to provide a method of manufacturing an electronic component having a coating film having high density (coating density) of a coating film while using a silane coupling agent.

In the method for manufacturing an electronic component according to the present invention, a first main surface and a second main surface, in which a plurality of ceramic layers and a plurality of internal electrodes are alternately stacked, are opposed to each other in the stacking direction, and are orthogonal to the stacking direction. A laminate including: a first side face and a second side face opposed to each other in a width direction; and a first end face and a second end face opposed to a length direction orthogonal to the lamination direction and the width direction; An electronic component body having an external electrode formed thereon so as to be electrically connected to the internal electrode; and an electronic component main body disposed at least from a part of the surface of the laminate to a part of the surface of the external electrode. a method of manufacturing an electronic component having a coating film that, and a step of obtaining an electronic component body, a step of stirring by a plurality of electronic components body stirring plate in agitation vessel provided with a plurality of electron state components body was stirred at a stirring for a container Includes a step of injecting the coating agent into the stirring vessel, and in the step of stirring the plurality of electronic components this body agitation vessel, depressurizing the agitating vessel and stirred for vessel by vacuum suction And, in the step of injecting the coating agent into the stirring container while heating the stirring container and injecting the coating agent into the stirring container, the injection is performed when the temperature in the stirring container reaches the volatilization temperature of the coating agent or higher. This is a method for manufacturing an electronic component, in which after the coating agent is injected into the inside, the coating agent is injected again when the temperature in the stirring container reaches the volatilization temperature of the coating agent again.
In the method of manufacturing an electronic component according to the present invention, it is preferable that the step of injecting the coating agent into the container is repeatedly performed a plurality of times.
Further, in the method for manufacturing an electronic component according to the present invention, the coating agent is preferably a silane coupling agent.
In the method for manufacturing an electronic component according to the present invention, it is preferable that the concentration of the silane coupling agent is 0.001 wt% or more and 0.05 wt% or less.
Still further, in the method for manufacturing an electronic component according to the present invention, it is preferable that a volatilization temperature of the coating agent in a vacuum environment is 40 ° C or higher and 60 ° C or lower.

The method for manufacturing an electronic component according to the present invention includes a step of injecting the coating agent into the stirring container while the plurality of electronic component bodies are stirred in the stirring container. The drop frequency can be averaged, and the coating agent can be applied to the entire electronic component body.
Further, in the method of manufacturing an electronic component according to the present invention, in the step of stirring the plurality of electronic component bodies in the stirring container, the inside of the stirring container is evacuated to reduce the pressure in the stirring container. Stir while heating the stirring vessel. In this way, by evacuation of the stirring container, the volatilization temperature of the solvent (that is, the coating agent) can be lowered. That is, this makes it possible to lower the spray temperature and to efficiently spray the coating agent.
Furthermore, in the method for manufacturing an electronic component according to the present invention, in the step of injecting the coating agent into the stirring container, the coating agent is injected when the temperature in the stirring container reaches or exceeds the volatilization temperature of the coating agent, After the coating agent is sprayed into the stirring container, the coating agent is again sprayed when the temperature in the stirring container reaches or exceeds the volatilization temperature of the coating agent. The coating agent can be sprayed in a targeted manner, and a dense film structure can be formed.

  According to the present invention, it is an object of the present invention to provide a method for manufacturing an electronic component having a coating film having a high density (coating density) of a coating film while using a silane coupling agent.

  The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments for carrying out the invention with reference to the drawings.

FIG. 2 is a perspective view showing an example of a multilayer ceramic capacitor manufactured by the method for manufacturing an electronic component according to the present invention. FIG. 2 is an illustrative sectional view taken along line II-II of the multilayer ceramic capacitor shown in FIG. 1. FIG. 3 is an illustrative sectional view taken along line III-III of the multilayer ceramic capacitor shown in FIG. 1. FIG. 3 is an enlarged schematic view of the vicinity of an external electrode of the multilayer ceramic capacitor shown in FIG. 2. FIG. 3 is an illustrative view showing one example of a coating apparatus used in a step of forming a coating film on a capacitor element;

1. Multilayer Ceramic Electronic Component A multilayer ceramic electronic component according to this embodiment will be described. In this embodiment, a multilayer ceramic capacitor is shown as an example of a multilayer ceramic electronic component manufactured by the method for manufacturing an electronic component according to the present invention.

  As shown in FIGS. 1, 2 and 3, multilayer ceramic capacitor 10 includes, for example, capacitor element 12 which is an electronic component body. The capacitor element 12 includes a rectangular parallelepiped laminate 14.

  The laminate 14 has a plurality of stacked ceramic layers 16 and a plurality of internal electrode layers 18. Further, the stacked body 14 includes a first main surface 14a and a second main surface 14b facing the stacking direction x, and a first side surface 14c and a second side surface facing the width direction y orthogonal to the stacking direction x. 14d, and a first end face 14e and a second end face 14f facing in the length direction z orthogonal to the stacking direction x and the width direction y. This laminate 14 preferably has rounded corners and ridges. In addition, the corner portion is a portion where three adjacent surfaces of the laminate intersect, and the ridge portion is a portion where two adjacent surfaces of the laminate intersect.

  The ceramic layer 16 includes an outer layer 16a and an inner layer 16b. The outer layer portion 16a is located on the first main surface 14a side and the second main surface 14b side of the multilayer body 4, and is formed between the first main surface 14a and the internal electrode layer 18 closest to the first main surface 14a. The ceramic layer 16 is located between them, and the ceramic layer 16 is located between the second main surface 14b and the internal electrode layer 18 closest to the second main surface 14b. The region sandwiched between the outer layer portions 16a is the inner layer portion 16b.

The ceramic layer 16 can be formed, for example, of a dielectric material. As the dielectric material, for example, a dielectric ceramic containing a component such as BaTiO ₃ , CaTiO ₃ , SrTiO ₃ , or CaZrO ₃ can be used. When the above dielectric material is contained as a main component, the content is smaller than the main components such as a Mn compound, an Fe compound, a Cr compound, a Co compound, and a Ni compound depending on the desired characteristics of the multilayer ceramic capacitor 10. You may use what added the component.

When a piezoelectric ceramic is used for the laminate 14, the multilayer ceramic electronic component functions as a ceramic piezoelectric element. Specific examples of the piezoelectric ceramic material include, for example, a PZT (lead zirconate titanate) -based ceramic material.
When a semiconductor ceramic is used for the laminate 14, the multilayer ceramic electronic component functions as a thermistor element. Specific examples of the semiconductor ceramic material include, for example, a spinel ceramic material.
When a magnetic ceramic is used for the laminate 14, the multilayer ceramic electronic component functions as an inductor element. When functioning as an inductor element, the internal electrode layer 18 is a coil-shaped conductor. Specific examples of the magnetic ceramic material include, for example, a ferrite ceramic material.

  The thickness of the fired ceramic layer 16 is preferably 0.5 μm or more and 10 μm or less.

As shown in FIGS. 2 and 3, the stacked body 14 has, as the plurality of internal electrode layers 18, a plurality of first internal electrode layers 18 a and a plurality of second internal electrode layers 18 b having, for example, a substantially rectangular shape. The plurality of first internal electrode layers 18a and the plurality of second internal electrode layers 18b are embedded so as to be alternately arranged at equal intervals along the stacking direction x of the stacked body 14.
On one end side of the first internal electrode layer 18a, a first extraction electrode portion 20a extended to the first end face 14e of the multilayer body 14 is provided. On one end side of the second internal electrode layer 18b, a second extraction electrode portion 20b extended to the second end face 14f of the multilayer body 14 is provided. Specifically, the first extraction electrode portion 20a on one end side of the first internal electrode layer 18a is exposed on the first end face 14e of the multilayer body 14. The second extraction electrode portion 20b on one end side of the second internal electrode layer 18b is exposed on the second end face 14f of the multilayer body 14.

  The laminate 14 includes a counter electrode portion 22a in the inner layer portion 16b of the ceramic layer 16 in which the first internal electrode layer 18a and the second internal electrode layer 18b face each other. The stacked body 14 is formed between one end in the width direction y of the counter electrode portion 22a and the first side surface 14c and between the other end in the width direction y of the counter electrode portion 22a and the second side surface 14d. (Hereinafter, referred to as “W gap”) 22 b of the stacked body 14. Further, the stacked body 14 is provided between the second end face 14f and the end of the first internal electrode layer 18a opposite to the first extraction electrode section 20a and the second internal electrode layer 18b. An end portion (hereinafter, referred to as “L gap”) 22c of the stacked body 14 formed between the end portion opposite to the extraction electrode portion 20b and the first end surface 14e is included.

  The internal electrode layer 18 contains, for example, a metal such as Ni, Cu, Ag, Pd, an Ag-Pd alloy, and Au. The internal electrode layer 18 may further include dielectric particles having the same composition as the ceramic contained in the ceramic layer 16.

External electrodes 24 are formed on the first end face 14e side and the second end face 14f side of the multilayer body 14. The external electrode 24 has a first external electrode 24a and a second external electrode 24b.
A first external electrode 24a is formed on the first end face 14e side of the multilayer body 14. The first external electrode 24a covers the first end surface 14e of the multilayer body 14, extends from the first end surface 14e, and extends from the first main surface 14a, the second main surface 14b, the first side surface 14c, and the first side surface 14c. The second side surface 14d is formed so as to cover a part of the side surface 14d. In this case, the first external electrode 24a is electrically connected to the first extraction electrode portion 20a of the first internal electrode layer 18a.
A second external electrode 24b is formed on the second end face 14f side of the multilayer body 14. The second external electrode 24b covers the second end face 14f of the stacked body 14, extends from the second end face 14f, and extends from the first main face 14a, the second main face 14b, the first side face 14c, and the second side face 14c. The second side surface 14d is formed so as to cover a part of the side surface 14d. In this case, the second external electrode 24b is electrically connected to the second extraction electrode section 20b of the second internal electrode layer 18b.

  In the stacked body 14, the capacitance is formed by the first internal electrode layer 18a and the second internal electrode layer 18b facing each other via the ceramic layer 16 in each counter electrode portion 22a. Therefore, a capacitance can be obtained between the first external electrode 24a connected to the first internal electrode layer 18a and the second external electrode 24b connected to the second internal electrode layer 18b. . Therefore, the multilayer ceramic electronic component having such a structure functions as a capacitor element.

  As shown in FIG. 2, FIG. 3, or FIG. 4, the first external electrode 24a has a base electrode layer 26a and a plating layer 28a in order from the stacked body 14 side. Similarly, the second external electrode 24b has a base electrode layer 26b and a plating layer 28b in order from the stacked body 14 side.

Each of the base electrode layers 26a and 26b includes at least one selected from a baking layer, a resin layer, a thin film layer, and the like. Here, the base electrode layers 26a and 26b formed of the baking layers will be described.
The baking layer includes glass and metal. The glass of the baking layer contains at least one selected from Si, B, Pb, Be, and the like. Further, the metal of the baking layer includes, for example, at least one selected from Cu, Ni, Ag, Pb, an Ag-Pb alloy, Au and the like. The baking layer may be a plurality of layers. The baked layer is obtained by applying a conductive paste containing glass and metal to the laminate 14 and baking it. The baked layer may be baked simultaneously with the ceramic layer 16 and the internal electrode layer 18. May be baked after firing. The thickness of the thickest part of the baking layer is preferably 5 μm or more and 100 μm or less.

A resin layer containing conductive particles and a thermosetting resin may be formed on the surface of the baked layer. Note that the resin layer may be formed directly on the laminate 14 without forming a baking layer. Further, the resin layer may be a plurality of layers. The thickness of the thickest part of the resin layer is preferably 5 μm or more and 100 μm or less.
The thin film layer is formed by a thin film forming method such as a sputtering method or a vapor deposition method, and is a layer of 1 μm or less on which metal particles are deposited.

Further, as the plating layers 28a and 28b, for example, at least one metal selected from Cu, Ni, Sn, Ag, Pd, an Ag-Pd alloy, Au, Bi, Zn, or the like, or an alloy containing the metal is used. .
The plating layers 28a and 28b may be formed by a plurality of layers. The plating layers 28a and 28b have a two-layer structure including first plating layers 30a and 30b provided on the surface of the baking layer, and second plating layers 32a and 32b provided on the surfaces of the first plating layers 30a and 30b. It is preferred that

  It is preferable to use Ni for the first plating layers 30a and 30b. The first plating layers 30a and 30b using Ni are used to prevent the base electrode layers 26a and 26b from being eroded by solder when mounting the multilayer ceramic capacitor. In the case where the internal electrode layer 18 contains Ni, it is preferable to use Cu having a good bonding property with Ni as the first plating layers 30a and 30b.

Further, it is preferable to use Sn or Au for the second plating layers 32a and 32b. The second plating layers 32a and 32b using Sn or Au are used for improving the wettability of solder when mounting the multilayer ceramic capacitor so that it can be easily mounted. The second plating layers 32a and 32b are formed as needed, and the external electrodes 24 are provided directly on the laminate 14 and are directly connected to the internal electrode layers 18 by the plating layers 28a and 28b, That is, it may be composed of the first plating layer. However, a catalyst may be provided on the laminate 14 as a pretreatment.
Further, the second plating layer may be provided as the outermost layer of the plating layers 28a and 28b, and another plating layer may be provided on the surface of the second plating layer.

  The thickness per plating layer is preferably 1 μm or more and 10 μm or less. Further, it is preferable that the plating layers 28a and 28b do not contain glass. Further, the plating layers 28a and 28b preferably have a metal ratio of 99% by volume or more per unit volume. The plating layers 28a and 28b are formed by grain growth along the thickness direction, and have a columnar shape.

The length of the multilayer ceramic capacitor 10 including the multilayer body 14, the first external electrode 24a, and the second external electrode 24b in the length direction z is L, and the multilayer body 14, the first external electrode 24a, and the second The dimension in the laminating direction x of the multilayer ceramic capacitor 10 including the external electrodes 24b is T, and the dimension in the width direction y of the multilayer ceramic capacitor 10 including the multilayer body 14, the first external electrode 24a, and the second external electrode 24b. Is the W dimension.
The dimensions of the multilayer ceramic capacitor 10 are such that the L dimension in the length direction z is 0.6 mm or more and 3.2 mm or less, the T dimension in the lamination direction x is 0.3 mm or more and 2.5 mm or less, and the W dimension in the width direction y is 0. 3 mm or more and 2.5 mm or less. Note that the L dimension in the length direction z is not always longer than the W dimension in the width direction y. The dimensions of the multilayer ceramic capacitor 10 can be measured with a microscope.

  In the multilayer ceramic capacitor 10 shown in FIGS. 1, 2 and 3, a coating film 34 is arranged so as to cover the entire capacitor element 12 constituted by the laminate 14 and the external electrodes 24.

The coating film 34 may be arranged so as to extend from at least a part of the surface of the multilayer body 14 to a part of the surface of the external electrode 24.
By arranging the coating film 34 so as to extend from at least a part of the surface of the multilayer body 14 to a part of the surface of the external electrode 24, it is possible to impart water repellency and waterproofness to the surface of the multilayer ceramic capacitor 10. . Therefore, when dew condensation occurs, water is repelled / waterproofed to prevent water droplets generated by the dew condensation from straddling between the electrodes, and ionization / precipitation of the external electrode can be suppressed. Can be suppressed.
When the coating film 34 is arranged so as to cover the entire capacitor element 12 constituted by the laminate 14 and the external electrodes 24 as in the present embodiment, the effect of suppressing the occurrence of ion migration becomes more remarkable. can do.

  The linear carbon number of the coating film 34 is preferably about 20. Accordingly, the main chains are folded, so that a three-dimensional film can be formed, and a highly dense film structure can be obtained. As a result, a migration resistance effect can be effectively provided.

  The coating film 34 contains a silane coupling agent. Of course, the coating film 34 may be made of only a silane coupling agent.

  The silane coupling agent preferably has a structurally bent bond in the main chain of the silane coupling agent. For example, a structure having an ether bond or an amide bond is preferable. Accordingly, the main chains are folded, so that a three-dimensional film can be formed, and a highly dense film structure can be obtained. As a result, a migration resistance effect can be effectively provided.

  The solvent for the silane coupling agent preferably contains an alkane, ketone, alcohol, isoparaffin, xylene, or solvent.

  By forming the coating film 34 using a silane coupling agent, the silane coupling agent is strongly bonded to the OH group, and thus preferentially adheres to the surface of the laminate 14. On the other hand, since a thin and uniform natural oxide film exists on the surfaces of the plating layers 28a and 28b, the coating film 34 can be thinly and uniformly applied thereto.

  Further, the silane coupling agent has F in the functional group and is preferably a long linear one.

  The concentration of the solid content of the silane coupling agent is generally 0.1% by weight or more and less than 3.0% by weight or less, that is, 0.001% by weight or more and 0.05% by weight or less used when performing the silane coupling agent treatment. It is.

The thickness of the coating film 34 is preferably 0.5 nm or more.
The method for measuring the thickness of the coating film 34 is as follows.
That is, the thickness of the coating film 34 is determined by first polishing the LT surface of the multilayer ceramic capacitor 10 as a sample along the length direction L to the center (１ ／ of the W dimension) of the sample, and mounting the cross-section. The two e-ends of the external electrode on the main surface opposite to the substrate can be measured by SEM or focused ion beam processing (FIB).

2. Next, a method for manufacturing an electronic component according to the present invention will be described. Hereinafter, a method of manufacturing the multilayer ceramic capacitor 10 will be mainly described.

(1) Manufacturing Process of Capacitor Element (Electronic Component Body) First, a ceramic green sheet and a conductive paste for an internal electrode are prepared. The ceramic green sheet and the conductive paste for the internal electrode include a binder (for example, a known organic binder) and a solvent (for example, an organic solvent).

  Next, a conductive paste for an internal electrode is printed on the ceramic green sheet in a predetermined pattern by, for example, screen printing or gravure printing to form an internal electrode pattern. Thus, a ceramic green sheet for the inner layer on which the internal electrode pattern is printed is manufactured. Further, a ceramic green sheet for an outer layer on which no internal electrode pattern is printed is also prepared.

  Then, a predetermined number of ceramic green sheets for the outer layer on which the internal electrode pattern is not printed are laminated, a ceramic green sheet for the inner layer on which the internal electrode pattern is printed is sequentially laminated on the surface, and the ceramic for the outer layer is laminated on the surface. A laminated sheet is manufactured by laminating a predetermined number of green sheets.

  Further, the laminated sheet is pressed in the laminating direction by means such as isostatic pressing to produce a laminated block.

  Subsequently, the laminated chip is manufactured by cutting the laminated block into a predetermined size. At this time, the corners and ridges of the laminated chip may be rounded by barrel polishing or the like.

  Next, a laminated body is manufactured by firing the laminated chip. The firing temperature depends on the material of the ceramic and the internal electrode, but is preferably 900 ° C. or more and 1300 ° C. or less.

  At this time, the first extraction electrode portion 20a of the first internal electrode layer 18a is exposed from the first end face 14e of the multilayer body 14. Then, the base electrode layer 26a of the first external electrode 24a is formed so as to cover the first extraction electrode portion 20a of the first internal electrode layer 18a exposed from the first end face 14e of the multilayer body 14. Is done. Further, the second extraction electrode portion 20b of the second internal electrode layer 18b is exposed from the second end face 14f of the multilayer body 14. Then, the base electrode layer 26b of the second external electrode 24b is formed so as to cover the second extraction electrode portion 20b of the second internal electrode layer 18b exposed from the second end face 14f of the multilayer body 14. Is done.

  In order to form the base electrode layer 26a of the first external electrode 24a, for example, the first extraction electrode portion 20a of the first internal electrode layer 18a exposed from the first end face 14e of the multilayer body 14 is exposed. A conductive paste for an external electrode is applied to the portion and baked. Similarly, in order to form the base electrode layer 26b of the second external electrode 24b, for example, the second extraction electrode of the second internal electrode 18b exposed from the second end face 14f of the multilayer body 14 is formed. The conductive paste for external electrodes is applied to the exposed portion of the portion 20b and baked. At this time, the baking temperature is preferably 700 ° C. or more and 900 ° C. or less. If necessary, one or more plating layers 28a and 28b are formed on the surfaces of the base electrode layers 26a and 26b to form the external electrodes 24.

  In order to form the base electrode layer 26a of the first external electrode 24a, for example, the first extraction electrode portion 20a of the first internal electrode layer 18a exposed from the first end face 14e of the multilayer body 14 is formed. May be subjected to plating. Similarly, in order to form the base electrode layer 26b of the second external electrode 24b, for example, the second extraction of the second internal electrode layer 18b exposed from the second end face 14f of the multilayer body 14 is performed. The exposed portion of the electrode portion 20b may be plated. When performing the plating treatment, either electrolytic plating or electroless plating may be employed. However, electroless plating requires a pretreatment with a catalyst or the like in order to improve the plating deposition rate, which complicates the process. There is a disadvantage. Therefore, it is usually preferable to employ electrolytic plating. It is preferable to use a barrel plating method as the plating method. When the surface conductor is formed, a surface conductor pattern may be printed on the surface of the outermost ceramic green sheet in advance and fired simultaneously with the laminate 14, or the main surface of the fired laminate 14 may be formed. The surface conductor may be printed thereon and then baked. If necessary, one or more plating layers 28a and 28b are formed on the surfaces of the base electrode layers 26a and 26b, and the external electrodes 24 are formed.

  As described above, capacitor element 12 shown in FIG. 1 is manufactured.

(2) Step of Forming Coating Film Next, a method of manufacturing the multilayer ceramic capacitor 10 by forming the coating film 34 on the capacitor element 12 will be described.

First, the coating device 40 used in the process of forming a coating film will be described. FIG. 5 is an illustrative view showing a coating apparatus used in a process of forming a coating film on a capacitor element.
The coating device 40 includes a housing 42. Inside the housing 42, a stirring container 44 for housing and stirring the capacitor element 12, which is an electronic component body, is arranged. A heater 46 for warming the stirring vessel 44 is attached to the upper and lower sides of the side surface inside the housing 42. The heater 46 controls the temperature in the stirring vessel 44 to be equal to or higher than the volatilization temperature of the coating agent.

  The stirring container 44 includes a main body 44a formed in a substantially cylindrical shape. The stirring vessel 44 has an opening 44b on one side of the main body 44a for receiving the condenser element 12, and a lid 44c is fitted into the opening 44b. In addition, the stirring container 44 has a bottom surface 44d on the other side of the main body portion 44a. Further, a rotation driving means (not shown) is connected to the stirring container 44. The stirring container 44 can be rotated by the rotation driving means, and the plurality of capacitor elements 12 can be stirred in the rotating stirring container 44. A plurality of agitating plates 48 for agitating the plurality of capacitor elements 12 well (ie, so that the coating surfaces of the plurality of capacitor elements 12 are evenly applied) are provided in the agitating container 44. . The plurality of stirring plates 48 are obliquely arranged side by side from the base portion 48a attached to the inner surface of the main body portion 44a of the stirring container 44 to the opening portion 44b.

  Further, a first pipe 50 is connected to the stirring container 44. One end of the first pipe 50 penetrates into the stirring vessel 44 via the lid 44c of the stirring vessel 44. The other end of the first pipe 50 is connected to a vacuum pump (not shown) for reducing the pressure inside the stirring vessel 44.

  Further, a second pipe 52 is connected to the stirring container 44. The second pipe 52 is provided in the stirring container 44 and is provided for spraying the coating agent onto the capacitor element 12 to be stirred. One end of the second pipe 52 penetrates into the stirring vessel 44 via the lid 44c of the stirring vessel 44, and sprays a coating agent on one end of the second pipe 52. Nozzle 52a is arranged. The nozzle 52a is arranged at a substantially central portion in the stirring container 44. The other end of the second pipe 52 is inserted into a coating agent container 56 filled with a liquid coating agent 54. Further, a valve 58 is disposed at an intermediate portion of the second pipe 52. The valve 58 is provided for adjusting the spray amount of the coating agent 54.

Here, it is preferable to use a silane coupling agent for the coating agent 54.
By using a silane coupling agent for the coating agent 54, the fixation of the capacitor element 12 to the ceramic is strengthened, and the original water repellency can be maintained even when an external force such as friction is applied.

Further, the solid content concentration of the silane coupling agent used in the coating agent 54 is preferably 0.001 wt% or more and 0.05 wt% or less.
As described above, by keeping the solid content concentration of the silane coupling agent relatively low, it is possible to reduce the influence of steric hindrance due to the linear chain of the silane coupling agent, and obtain a dense film structure. It can be easier.
When the solid concentration of the silane coupling agent is treated at a high concentration, the silane coupling agents (basic units) physically interfere with each other, and the proportion of the silane coupling agent in contact with the ceramic surface of the laminate 14 decreases, while the silane coupling agent decreases. When the solid content concentration is low, there is no physical interference, and the solid surface can reliably contact the ceramic surface of the capacitor element 12. Therefore, by spraying the coating agent 54 a plurality of times while ensuring that the silane coupling agent is in contact with the ceramic surface of the capacitor element 12 at a low solid content concentration, the adhesion to the laminate 14 is good, and It is possible to obtain a high film structure.

  Further, the volatilization temperature of the coating agent 54 in a vacuum environment varies depending on the material of the coating agent 54, but it is preferable to use one having a temperature of 40 ° C or higher and 60 ° C or lower.

Subsequently, a process of forming a coating film using a coating apparatus will be described.
First, the capacitor element 12 manufactured in the above-described capacitor element manufacturing process is prepared. Next, the prepared capacitor element 12 is stored in a stirring container 44 that can store the capacitor element 12. Then, the stirring container 44 in which the capacitor element 12 is stored is rotated by the rotation driving means to stir the capacitor element 12.

  Subsequently, the coating agent 54 is ejected from the nozzle 52a while the capacitor element 12 is being stirred. In this way, by spraying the coating agent 54 in a state where the plurality of capacitor elements 12 are agitated, the frequency of dropping on the capacitor elements 12 can be averaged, and the coating agent 54 is applied to the entire capacitor elements 12. can do.

  In the step of stirring the plurality of capacitor elements in the stirring vessel, the inside of the stirring vessel 44 is evacuated by a vacuum pump, and the inside of the stirring vessel 44 is stirred under reduced pressure. The vacuum pressure in the stirring vessel 44 in this reduced pressure state is preferably -60 kPa or less as a relative pressure (gauge pressure). In this manner, by evacuation of the inside of the stirring container 44, the volatilization temperature of the solvent can be lowered. That is, since the spray temperature can be lowered, and the injection cycle can be accelerated, the injection of the coating agent 54 can be performed efficiently.

  In the step of stirring the plurality of capacitor elements in the stirring vessel, the stirring vessel 44 is stirred in an atmosphere heated by the heater 46. The heater 46 is controlled so that the temperature in the stirring container 44 becomes equal to or higher than the volatilization temperature of the coating agent 54.

  In the step of injecting the coating agent into the stirring container, the coating agent 54 is injected when the atmosphere in the stirring container 44 reaches a temperature equal to or higher than the volatilization temperature of the coating agent 54 by heating by the heater 46. Thereby, the coating agent 54 can be sprayed on the surface of the laminate 14 multiple times, and a dense film structure can be formed. The volatilization temperature here is, specifically, the volatilization temperature of the coating agent 54 when the inside of the stirring vessel 44 is in a vacuum state.

  The volatilization temperature of the coating agent 54 in a vacuum environment varies depending on the material of the coating agent 54, but it is preferable to use one having a temperature of 40 ° C or higher and 60 ° C or lower.

  By injecting the coating agent 54 when the atmosphere in the stirring container 44 reaches the volatilization temperature of the coating agent 54, the injected coating agent 54 evaporates within a few seconds after touching the capacitor element 12. Due to the heat of vaporization at this time, the temperature in the stirring vessel 44 decreases. Since the temperature around the stirring container 44 is kept higher than the temperature at which the coating agent 54 in the stirring container 44 is sprayed, the temperature inside the stirring container 44 rises, and the coating agent 54 evaporates again. When the temperature reaches the temperature, the coating agent 54 is injected again. Therefore, it becomes possible to spray the coating agent 54 efficiently. In addition, when the coating agent 54 reaches the volatilization temperature, by spraying the coating agent 54, it is possible to minimize dry coagulation of the solute, and it is possible to suppress coat unevenness due to dry coagulation.

  In the above-described coating film forming step, a plurality of media may be placed in the stirring container 44 as needed to stir the capacitor element 12.

  Through the above steps, the multilayer ceramic capacitor 10 having the coating film 34 formed by the coating agent 54 is obtained.

  According to the method for manufacturing an electronic component according to this embodiment, the method includes a step of injecting a coating agent into the stirring container while the plurality of capacitor elements 12 as the electronic component bodies are stirred in the stirring container 44. Therefore, the frequency of deposition of the coating agent 54 on the capacitor element 12 can be averaged, and the coating agent 54 can be applied to the entire capacitor element 12.

  Further, according to the method for manufacturing an electronic component according to the present embodiment, in the step of stirring a plurality of capacitor elements in the stirring vessel, the inside of the stirring vessel 44 is evacuated to reduce the pressure inside the stirring vessel 44. Then, the stirring vessel 44 is further stirred while being heated. In this manner, by evacuation of the stirring container 44, the volatilization temperature of the solvent (that is, the coating agent 54) can be lowered. In other words, this makes it possible to lower the spray temperature and to efficiently spray the coating agent 54.

  Furthermore, according to the method of manufacturing an electronic component according to the present embodiment, in the step of injecting the coating agent into the stirring container, when the temperature in the stirring container 44 reaches the volatilization temperature of the coating agent 54 or higher. After injecting the coating agent 54 and injecting the coating agent 54 into the stirring container 44, when the temperature in the stirring container 44 reaches the volatilization temperature of the coating agent 54 or more again, the coating agent 54 is Is sprayed, so that the coating agent 54 can be sprayed on the surface of the laminate 14 multiple times, and a dense film structure can be formed.

  In the step of injecting the coating agent 54 into the agitating container 44, it is preferable to perform the injection repeatedly a plurality of times. Specifically, by performing the step of injecting the coating agent 54 twice or more, the above-described effect of the present invention can be further improved.

  The effects of the multilayer ceramic electronic component obtained as described above will be apparent from the following experimental examples.

3. Experimental Examples Hereinafter, experimental examples performed by the inventors to confirm the effects of the present invention will be described.

(1) Experimental example 1
In Experimental Example 1, for the multilayer ceramic capacitor, samples were prepared in which the number of sprays of the coating agent on the capacitor element was changed, a dew condensation cycle test was performed for each sample, and evaluation was performed based on the number of occurrences of ion migration.

The specifications of the capacitor elements of the samples of Examples 1 to 7 and Comparative Example 1 prepared for the above evaluation are as follows. Note that dimensions such as size are design values. The production of the capacitor element was performed by the production process of the capacitor element according to the present embodiment.
Size: L × W × T = 1.6mm × 0.8mm × 0.8mm
Material of ceramic layer: BaTiO ₃
Capacity: 0.1μF
Rated voltage: 50V
Material of internal electrode layer: Ni
Structure of external electrode Base electrode layer: electrode containing metal powder (Cu) and glass First plating layer: Ni
Second plating layer: Sn

The specifications of the coating agent used for forming the coating film in the multilayer ceramic capacitors of the samples of Examples 1 to 7 are as follows. The formation of the coating film was performed by the step of forming the coating film according to the present embodiment.
Material of coating agent: silane coupling agent (Shin-Etsu Chemical Co., Ltd .: KY-108 coating agent)
Solid content concentration of coating agent: see Table 1 Volatility temperature of coating agent (in vacuum): about 50 ° C

On the other hand, the coating film in the multilayer ceramic capacitor of the sample of Comparative Example 1 was formed as follows.
That is, first, the chip of the capacitor element was put into a net basket with a handle, and the net basket was immersed in a stainless bat containing a coating agent for 10 minutes. After a certain period of time, the net basket was pulled up, and the excess coating agent was suction-dried. Thereafter, the net basket was immersed in a stainless steel vat containing only the diluting solvent (of the coating agent) for 10 minutes, and then the excess diluting solvent was suction-dried.

(Method of confirming ion migration)
After the sample was solder-mounted on the board, a condensation cycle test was performed. As a condition of the dew condensation cycle test, the multilayer ceramic capacitor used for the test is held for 1 hour in a low temperature environment of -30 ° C., and then for 1 hour in a high temperature and high humidity environment of 25 ° C. and 90% humidity. It was kept (1 WV (25 V in this test)) and finally dehumidified at a temperature of 25 ° C. for 1.5 hours and dried. This was defined as one cycle, and 48 cycles were performed alternately between low temperature and high temperature and high humidity. The evaluation criterion was determined to be NG when it was confirmed by observation with a microscope at a magnification of 100 that white or black ion migration products were present on the surface of the sample multilayer ceramic capacitor after the test. When a product by ion migration is analyzed using a wavelength-dispersive X-ray spectrometer (WDX), Sn, Ni, or Cu can be detected, whereby it is confirmed that the product is due to ion migration. did. In each of the examples and comparative examples, the number of samples used in the condensation cycle test was 36.

  Table 1 shows the evaluation results of the samples of Examples 1 to 7 and Comparative Example 1 by the condensation cycle test.

  From the above results, in the multilayer ceramic capacitor manufactured by the method for manufacturing an electronic component of the present invention, a method for manufacturing a multilayer ceramic capacitor having a coating film with high film density (coating density) while using a silane coupling agent. It has become clear that can be provided.

(2) Experimental example 2
In Experimental Example 2, for the multilayer ceramic capacitor, samples in which the solid content of the silane coupling agent as a coating agent was changed were prepared, and a dew condensation cycle test was performed on each sample, and the evaluation was performed based on the number of occurrences of ion migration. went.

The specifications of the capacitor elements of the samples of Examples 8 to 12 and Comparative Examples 2 to 7 prepared for the above evaluation are as follows. Note that dimensions such as size are design values. The production of the capacitor element was performed by the production process of the capacitor element according to the present embodiment.
Size: L × W × T = 1.6mm × 0.8mm × 0.8mm
Material of ceramic layer: BaTiO ₃
Capacity: 0.1μF
Rated voltage: 50V
Material of internal electrode layer: Ni
Structure of external electrode Base electrode layer: electrode containing metal powder (Cu) and glass First plating layer: Ni
Second plating layer: Sn

The specifications of the coating agent used for forming the coating film in the multilayer ceramic capacitors of the samples of Examples 8 to 12 are as follows. The formation of the coating film was performed by the step of forming the coating film according to the present embodiment.
Material of coating agent: silane coupling agent (Shin-Etsu Chemical Co., Ltd .: KY-108 coating agent)
Solid content concentration of coating agent: see Table 2 Volatility temperature of coating agent (in vacuum): about 50 ° C

On the other hand, the coating films in the multilayer ceramic capacitors of the samples of Comparative Examples 2 to 7 were formed as follows.
That is, first, the chip of the capacitor element was put into a net basket with a handle, and the net basket was immersed in a stainless bat containing a coating agent for 10 minutes. After a certain period of time, the net basket was pulled up, and the excess coating agent was suction-dried. Thereafter, the net basket was immersed in a stainless steel vat containing only the diluting solvent (of the coating agent) for 10 minutes, and then the excess diluting solvent was suction-dried.

(Method of confirming ion migration)
The method of confirming ion migration for each sample was performed in the same manner as in Experimental Example 1.

  Table 2 shows the evaluation results of the samples of Examples 8 to 12 and Comparative Examples 2 to 7 by the condensation cycle test.

From the above results, by using the method for manufacturing an electronic component of the present invention, it is possible to reduce the solid content of the silane coupling agent, and to reduce the effect of steric hindrance due to the linear chain of the silane coupling agent. And a highly dense film structure can be easily obtained. Specifically, it is preferable that the solid content concentration of the silane coupling agent is 0.001 wt% or more and 0.05 wt% or less. When the solid concentration of the silane coupling agent is 0.001% by weight or more and 0.05% by weight or less, ion migration does not occur.
On the other hand, in each of the samples of Comparative Examples 2 to 7, ion migration occurred in any of the samples of Comparative Examples, even if the solid content concentration of the silane coupling agent was the same as in the examples.

  As described above, according to the method for manufacturing an electronic component of the present invention, the silane coupling agent is reliably brought into contact with the ceramic surface of the capacitor element by making the solid content concentration of the silane coupling agent low. Further, by spraying a plurality of times, it is possible to obtain a film structure having good adhesion to the laminate and high density.

  It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the gist.

10 Multilayer ceramic capacitor 12 Capacitor element (electronic component body)
Reference Signs List 14 laminated body 16 ceramic layer 16a outer layer part 16b inner layer part 18 internal electrode layer 18a first internal electrode layer 18b second internal electrode layer 20a first lead electrode part 20b second lead electrode part 22a counter electrode part 22b side Part (W gap)
22c end (L gap)
Reference Signs List 24 external electrode 24a first external electrode 24b second external electrode 26a, 26b base electrode layer 28a, 28b plating layer 30a, 30b first plating layer 32a, 32b second plating layer 34 coating film 40 coating device 42 housing 44 Stirring container 44a Main unit 44b Opening 44c Cover 44d Bottom surface 46 Heater 48 Stirring plate 48a Base 50 First pipe 52 Second pipe 52a Nozzle 54 Coating agent 56 Coating agent container 58 Valve

Claims (5)

A first main surface and a second main surface, in which a plurality of ceramic layers and a plurality of internal electrodes are alternately laminated, facing each other in a laminating direction; a first side surface, facing in a width direction perpendicular to the laminating direction; A laminate including a second side surface, a first end face and a second end face opposed in a length direction orthogonal to the lamination direction and the width direction;
An external electrode formed on the laminate so as to be electrically connected to the internal electrode;
An electronic component body having
At least, a coating film disposed so as to span a part of the surface of the external electrode from a part of the surface of the laminate,
A method for manufacturing an electronic component having:
A step of obtaining the electronic component body;
Stirring the plurality of electronic component bodies in a stirring vessel provided with a stirring plate ,
In a state where the plurality of the electronic component Body allowed to stir at the agitation vessel, a step of injecting the coating agent to the agitation vessel,
Has,
In the step of stirring said plurality of said electronic components Body by the agitation vessel, the agitating vessel under vacuum said agitating vessel by vacuum suction, and the stirring vessel is stirred with heating ,
In the step of injecting the coating agent into the stirring container, when the temperature in the stirring container reaches the volatilization temperature of the coating agent or more, the injection is performed,
A method of manufacturing an electronic component, wherein after the coating agent is injected into the stirring container, the coating agent is injected again when the temperature in the stirring container reaches the volatilization temperature of the coating agent again.   The method for manufacturing an electronic component according to claim 1, wherein the step of injecting the coating agent into the container is repeatedly performed a plurality of times. The coating agent is a silane coupling agent, method for manufacturing the electronic component according to claim 1 or claim 2. The method for manufacturing an electronic component according to claim 3 , wherein the concentration of the silane coupling agent is 0.001 wt% or more and 0.05 wt% or less.   The method for manufacturing an electronic component according to claim 1, wherein a volatilization temperature of the coating agent in a vacuum environment is 40 ° C. or more and 60 ° C. or less.

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