JPH09119000A - Manufacture of electronic parts and barrel plating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of electronic parts in which electronic parts having a plated film with less variance in thickness can be obtained in a relatively short time, and properties such as the thermal impact resistance of the electronic parts can be improved. SOLUTION: This manufacturing method of electronic parts has the process in which an electronic parts 33 and a medium 34 are charged in a barrel of a barrel plating device 21, the device is immersed in the plating solution, and realizing energization while the barrel is rotated to form the plated film on the surface of the electronic parts 33, and the barrel plating device has rectifying bodies 30, 31 arranged so as to be extended to deflected parts 26b, 27b sides of the cathode rays 26, 27 from the center of end faces 23, 24 by closing each end of a barrel body 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electronic part having an improved step of forming an electrode on the outer surface of the electronic part, and an improvement of a barrel plating apparatus used in such a manufacturing method.

[0002]

2. Description of the Related Art An example of a conventional method of manufacturing an electronic component will be described by taking a chip type multilayer capacitor as an example.

The multilayer capacitor 1 has a sintered body 2 made of a dielectric ceramic such as barium titanate. Inside the sintered body 2, internal electrodes 3a to 3e are arranged so as to overlap with each other via a ceramic layer. Further, an external electrode 4 is formed on the end surface 2a of the ceramic sintered body 2, and an external electrode 5 is formed on the end surface 2b. External electrode 4,
Nos. 5A and 5B are baking layers 4a and 5a formed by applying a metal powder-containing conductive paste such as Ag on the end surfaces 2a and 2b and baking, and Ni formed by electroplating on the baking layers 4a and 5a. Layers 4b, 5b and N
Sn layers 4c and 5c also formed by electroplating on i layers 4b and 5b.

In manufacturing the multilayer capacitor 1, after preparing a ceramic sintered body 2 on which the internal electrodes 3a to 3e are formed, a conductive paste is applied to both end faces 2a and 2b of the sintered body 2 and baked. The baking layers 4a, 5
a is formed. Next, the Ni layers 4b and 5b and the Sn layers 4c and 5c are formed using a barrel plating apparatus.

The structure of the barrel plating apparatus is shown in FIGS.
This will be described with reference to FIG. The barrel plating device 6 has a structure in which end face materials 8 and 9 are fixed to both ends of the barrel body 7 so as to close the openings at both ends of the barrel body 7. As is apparent from FIG. 3, the end faces 8 and 9 are provided with the cathode wires 10 and 11, respectively.
Is inserted. The barrel body 7 is configured to be rotationally driven by a drive source (not shown). However, the positions of the cathode rays 10 and 11 are fixed as they are, as shown in FIG.

The cathode lines 10 and 11 are respectively provided with introductory portions 10a and 10a extending inward through the centers of the end face materials 8 and 9, respectively.
11a. The bent portions 10b and 11b are formed so as to be bent at the tips of the introduction portions 10a and 11a and extend toward the side surface of the barrel body 7. Also,
Tip portions 10c and 11c are provided on the tip ends of the bent portions 10b and 11b so as to extend toward the other end surface material side. In the cathode rays 10 and 11, only the above-mentioned tip portions 10c and 11c are exposed, and in the introduction portions 10a and 11a and the bent portions 10b and 11b, an insulating coating (not shown) is provided around the cathode rays. ing.

At the time of barrel plating, the medium 13 and the electronic component 14 are put into the barrel body 7, the barrel body 7 is immersed in the plating solution 12, and the cathode wires 10 and 11 are energized while rotating. Allows electronic components 1
A plating film is formed on the baking layer 4 (not shown). The medium 13 is made of a conductive material such as steel balls, and is provided to assist the electrical conduction between the cathode lines 10 and 11 and the electronic component 14. In FIG. 3, the media 13 and the electronic components 14 are illustrated as being separated and scattered, but in reality, the media 13 and the electronic components 14 are more densely distributed than in the illustrated state. Has been done.

While rotating the barrel body 7, the cathode ray 10,
The electric component 11 is agitated in the plating solution 12 by energizing, and the medium 13 is assisted in energizing to form a plating film having a desired film thickness on the baking layer. become.

[0009]

However, the electronic component 14 existing at the position shown by the arrow A in FIG. 3, that is, the end members 8 and 9, and the bent portions 10b and 11 of the cathode wires 10 and 11 are formed.
The electronic component 14 located between b and is difficult to be sufficiently stirred. Therefore, the electronic component 14 existing at the position indicated by the arrow A
Has a problem that it is less likely to be plated than the electronic component 14 located in the center, and the thickness of the plated film tends to vary. That is, in the electronic component 14 existing at the position indicated by the arrow A, there is a problem that the thickness of the plating film is hard to reach the target thickness.

However, if the plating time is lengthened and the barrel main body 7 is plated while rotating, it is possible to form a plating film of a desired thickness on the electronic component body 14 at the position indicated by arrow A as well. is there. However, when the plating time is lengthened, the plating solution 12 easily penetrates into the sintered body through the pores present in the baking layer of the external electrode, and especially between the internal electrode and the ceramic layer in the sintered body. There is a problem in that the thermal shock resistance of the obtained multilayer capacitor is deteriorated by penetrating inside from the interface.

Therefore, an object of the present invention is to provide a method capable of forming an electrode having a plating film having a small variation in thickness in a relatively short time and manufacturing an electronic component having excellent characteristics such as thermal shock resistance. Another object of the present invention is to provide a barrel plating apparatus that makes it possible to obtain such an electronic component.

[0012]

According to the present invention, an electronic component and a medium for assisting electrical conduction between the barrel and the electronic component are placed in the barrel of a barrel plating apparatus, and the barrel is filled with a plating solution. In a method of manufacturing an electronic component having a step of forming an electrode film on the surface of an electronic component by immersing, energizing while rotating, and forming an electrode film on the surface of the electronic component, the barrel plating device has a cylindrical shape whose both ends are closed by a pair of end face materials. The barrel body, an introduction portion extending inward from the center of the end face material, a bent portion bent at the tip of the introduction portion so as to extend to the side surface side of the barrel body, and the other end surface from the tip of the bent portion. A cathode wire having a tip portion extended to the material side and arranged so as not to rotate together with the barrel body, and extending from the vicinity of the center of the end surface material to the tip side of the bent portion of the cathode wire inside the end material. Characterized by using those having a rectifying body provided so that a method of manufacturing an electronic component.

In the method of manufacturing an electronic component of the present invention, the rectifying body is provided so as to extend from the center of the end face material or the vicinity thereof to the tip side of the bent portion of the cathode line.
Even if the electronic component enters the space between the end face material and the bent portion of the cathode line, the electronic component is smoothly moved to the center side of the barrel with respect to the bent portion. Therefore, it is possible to effectively reduce the variation in the plating film thickness of a large number of electronic components placed in the barrel.

Further, the barrel plating apparatus of the present invention is a barrel plating apparatus for plating electronic components immersed in a plating solution inside, and is a cylindrical barrel whose both ends are closed by a pair of end face materials. A main body, an introduction part extending inward from the center of the end face material, a bent part bent at the tip of the introduction part so as to extend to the side surface side of the barrel body, and the other end face material side from the tip of the bent part In the inside of the end face material of the barrel, which has a tip portion extended to, and is arranged so as not to rotate together with the barrel body,
And a rectifying body provided so as to extend from the center of the end face material toward the tip of the bent portion of the cathode wire.

In the barrel plating apparatus of the present invention, since the rectifying body is mounted on the barrel so as to extend from the vicinity of the center of the end face material toward the tip of the bent portion of the cathode wire, the action of the rectifying body causes the rectifying body to have a sharp edge. The electronic component provided between the bent portion and the bent portion of the cathode ray is smoothly moved to the central region of the barrel. Therefore, when plating a large number of electronic components placed in the barrel, it is possible to reduce variations in the thickness of the plated film.

[0016]

FIG. 4 is a perspective view showing the appearance of a barrel plating apparatus according to one embodiment of the present invention, and FIG.
FIG. 3 is a vertical sectional view showing its internal structure.

The barrel plating apparatus 21 of this embodiment has a barrel-shaped barrel body 22. Usually, a large number of through holes (not shown) are provided in the side wall of the barrel body 22 so that a plating solution, which will be described later, can pass therethrough. In this embodiment, the barrel body 22 has a hexagonal cross section.
Although it is configured as a rectangular tube, it may be configured so that the cross-sectional shape is another polygonal shape such as a quadrangle or a pentagon. Further, the barrel body 22 may have a cylindrical shape. However, in order to enhance the stirring effect of the electronic components inside and reduce the variation in the thickness of the plating film, it is desirable to configure the barrel main body 22 to have a rectangular tubular shape rather than a cylindrical shape.

On both end faces of the barrel body 22, the end face material 2
3, 24 are fixed, and the inside of the barrel body 22 is closed to form a barrel 25. The end members 23 and 24 may be formed integrally with the barrel body 22.

The material forming the barrel body 22 and the end face members 23, 24 is not particularly limited, but
It can be made of an appropriate rigid material such as metal or synthetic resin. The barrel 25 is configured to be rotatable around its axial direction by a rotary drive source such as a motor (not shown).

On the other hand, as is clear from FIG. 5, the end face material 2
Through holes 23a and 24a are formed in the centers of the holes 3 and 24, respectively. Cathode lines 26 and 27, whose positions are fixed so as not to rotate themselves, are inserted into the through holes 23a and 24a. The cathode lines 26 and 27 have through holes 23a,
It has introduction parts 26a and 27a which are inserted through 24a.
The introduction portions 26a and 27a are connected at their outer ends to a negative potential (not shown). The introduction parts 26a and 27a are
It is linearly extended in the barrel body 22 through the through holes 23a and 24a. The leading ends of the introducing portions 26a and 27a are bent so that the bending portions 26b and 27a are bent.
b. The bent portions 26b and 27b are extended such that the tip end side faces the side surface of the barrel body 22.

On the other hand, the cathode lines 26, 27 are bent again at the tips of the bent portions 26b, 27b, and the tip portions 26c, 27 are formed.
c is configured. The tip portions 26c and 27c are substantially parallel to the introduction portions 26a and 27a, that is, the other end surface material 2
It is extended to the 4,23 side.

Further, as is apparent from FIG. 5, the cathode ray 2
Insulation coatings 28 and 29 are formed around 6 and 27, and the insulation coatings 28 and 29 introduce the introduction portions 26a and 27a and the bent portions 26 so that the tip portions 26c and 27c are exposed.
b, 27b. The insulating coatings 28 and 29 are formed by adhering an appropriate insulating resin or the like around the cathode lines 26 and 27.

In the barrel 25, the end face materials 23,
Rectifiers 30 and 31 are attached to the inner surface of 24.
The rectifying body 30 is made of a material having an appropriate shape retention property such as synthetic resin or ceramics. This rectifying body 30
As shown in FIGS. 6A and 6B, has a triangular pyramid shape in which three vertices are present on the inner surface of the end face material 23 and the other one is located on the inner wall of the barrel body 22. ing.
Therefore, the surfaces 30 a and 30 b (see FIG. 6) exposed in the barrel body 22 of the rectifying body 30 are bent toward the central region of the barrel body 22 from the end face material 23.
(See FIG. 5).

An electronic component 33 and a medium 34 are placed in the barrel 25 and immersed in the plating solution 32 for plating. The electronic component 33 is not particularly limited, but a chip type ceramic electronic component such as a multilayer capacitor can be exemplified. In addition, the medium 34 is introduced to assist energization to the outer surface of the electronic component 33 when forming a plating film on the outer surface of the electronic component 33. Therefore, in reality, FIG.
More electronic components 33 and media 34 are loaded than shown in FIG.
The medium 34 functions so as to electrically connect 3 and 3.

Since the medium 34 is provided for assisting energization, it is made of a conductive material such as steel balls, or at least the surface thereof is made of a conductive material. Further, the shape of the medium 34 is not particularly limited, but in order to sufficiently exhibit the energization assisting action with the rotation of the barrel 25,
A spherical shape is desirable.

When plating is performed using the plating apparatus 21 of this embodiment, the barrel 25 is rotated from the state shown in FIG. In this case, since the electronic component 33 and the medium 34 are sufficiently agitated and mixed in the region between the tip portions 26c and 27c of the cathode rays 26 and 27, the plating film can be formed with a relatively small variation. . On the other hand, as described in the section of the prior art, the cathode ray 2
In the region between the bent portions 26b, 27b of 6, 27 and the end surface members 23, 24, stirring of the electronic component 33 is hindered. However, in this embodiment, since the rectifying bodies 30 and 31 are provided, the electronic component 33 is placed in the space indicated by the arrow C in FIG.
When the medium or medium 34 enters, the electronic component 33 and the medium 34 smoothly move along the outer wall of the rectifying body 30 as the barrel 25 rotates. That is, the cathode lines 26, 27
Will be moved toward the tip portions 26c, 27c of the barrel main body 22 and further toward the center of the barrel body 22. Therefore, it is possible to uniformly plate all the electronic components 33 that have been put in, and it is possible to suppress variations in the thickness of the plated film.

The rectifying body 30 is preferably constructed so that the dimension P in FIG. 5 is larger than the dimension Q in FIG. Here, the dimension P is the innermost end of the rectifying body 30,
The distance Q to the end face material 23 is shown.
2 shows the distance from the inner surface to the innermost portion of the bent portion 26b of the cathode wire 26. When the dimension P is smaller than the dimension Q, the electronic component element body and the medium 34 may be retained in the space between the bent portion 26b and the rectifying body 30, and the action of the rectifying body 30 is sufficiently exerted. There are things that you do not want to show. Therefore, it is preferable that the dimension P is equal to or greater than the dimension Q.

The rectifying bodies 30 and 31 are not limited to those having the above-described triangular pyramid shape, and the end face materials 23 and 24 are not limited thereto.
As long as the electronic component that has entered the space between the bent portion 26b and the bent portion 26b can be smoothly moved toward the central region of the barrel main body 22, the bent portion 26b, As long as it has a surface extending toward the tip side of 27b, it can be formed in an appropriate shape.

However, it is preferable that the rectifying body 30 has a triangular pyramid shape as in the present embodiment. This is due to the rotation of the barrel 25 and the electronic components 33 and the media 34.
Will be biased within the barrel, as shown in FIG. 7, which is a schematic cross-sectional view from the inside of the barrel. In this case, when the rectifying body 30 is a triangular pyramid, since the traverse line 30c exists, the electronic component 33 and the medium 34 are more smoothly moved to the central region side of the barrel 22 as the barrel 22 rotates. It will be. That is, it is possible to more effectively suppress the retention of the electronic component 33 and the medium 34 in the portion where the rectifying body 30 is provided.

[0030]

EXAMPLE Next, the Ni layer and the Sn layer were plated on the baked electrode of the multilayer capacitor using the barrel plating apparatus described in the above embodiment.

The prepared multilayer capacitor has a capacity of 1.6 × 0.
It has a size of 8 × 0.8 and 100 × 10 ³ pieces were placed in the barrel. The medium used was an iron ball having a diameter of 1.5 mm, and 150 × 10 ³ pieces were put into the barrel. At the time of plating, in both plating of the Ni layer and the Sn layer, a current of 20 A was applied and the barrel was rotated for 30 minutes for each plating.

For comparison, the barrel plating apparatus used is the conventional barrel plating apparatus shown in FIG.
N is the same as above except that the plating time is 60 minutes for each of the Ni layer and the Sn layer.
The i layer and the Sn layer were plated (comparative example).

As described above, the Ni layer and the Sn layer were plated, and the thickness of the plated film in the obtained multilayer capacitor was measured. The results are shown in Table 1 below.

[0034]

[Table 1]

The CV value in Table 1 is the standard deviation σ,
Σ / x × 1 where x is the average thickness of the plating film
It is a value represented by 00 (%). In addition, the measurement results of the thickness of the plating film shown in Table 1 are the measurement results of 50 laminated capacitors under each condition.

As is clear from Table 1, the CV value showing the degree of variation in the film thickness of the plated film is significantly reduced in the barrel plating apparatus of the example as compared with the comparative example.

Further, the minimum film thickness value (x-3σ) statistically calculated in one manufacturing lot is also thick in the case of the embodiment although the average film thickness is thin. Recognize. From this, by using the barrel plating apparatus of the example, the function of the plating film, that is, the solder heat resistance by the Ni plating layer and the solderability by the Sn plating layer are It can be seen that it can be secured as in the case of the comparative example.

Further, a thermal shock test was performed on the multilayer capacitors of Examples and Comparative Examples after the above-mentioned barrel plating. The thermal shock resistance test is conducted by immersing the plated multilayer capacitor in molten solder at 250 to 450 ° C. for 2 seconds and pulling it up.
After that, polishing was performed, and the presence or absence of cracks was observed. The results are shown in Fig. 8.

In FIG. 8, the solid line X shows the result of the example and the broken line Y shows the result of the comparative example. As is clear from FIG. 8, in the multilayer capacitors obtained in the examples, no cracks were generated even when the solder temperature was raised to 400 ° C., whereas the multilayer capacitors obtained in the comparative example were obtained. It can be seen that in the capacitor, cracks occur at a considerable rate at temperatures of 300 ° C. or higher.

Therefore, when the barrel plating apparatus of the comparative example is used, the variation in quality due to the penetration of the plating solution is large within the lot, and the thermal crack may occur at a relatively low temperature. When the barrel plating apparatus of the example is used, there is almost no variation in the above-mentioned quality deterioration within the lot, and it is considered that the heat resistance of all the multilayer capacitors is maintained at substantially the same level.

[0041]

In the method of manufacturing an electronic component and the barrel plating apparatus of the present invention, the rectifying body is attached to the barrel so as to extend from the vicinity of the center of the end face material of the barrel to the tip side of the bent portion of the cathode wire. When plating is carried out while rotating the barrel, the inserted electronic components and media smoothly move from the space between the end face material and the bent portion of the cathode line to the central region of the barrel. Therefore, it is possible to significantly reduce the variation in the thickness of the plating film formed during barrel plating. Moreover, since the electronic components are less likely to stay in the areas that are difficult to be plated, the time required for barrel plating can be significantly shortened, the productivity of electronic components can be effectively increased, and energy can be saved. You can

In addition, since the plating time can be shortened, it is possible to suppress the penetration of the plating solution into the electronic parts,
Therefore, it is possible to provide an electronic component having excellent thermal shock resistance. In particular, in a ceramic laminated electronic component, the plating solution may enter the sintered body from the interface between the internal electrode and the ceramic layer during plating, and the thermal shock resistance may decrease. Since the plating time can be shortened at the time of manufacturing, the present invention can be applied more effectively.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a multilayer capacitor.

FIG. 2 is a perspective view for explaining a conventional barrel plating apparatus.

FIG. 3 is a partially cutaway sectional view of a conventional barrel plating apparatus.

FIG. 4 is a perspective view showing the outer appearance of the barrel plating apparatus according to the embodiment of the present invention.

5 is a partially cutaway sectional view of the barrel plating apparatus shown in FIG.

6A and 6B are a schematic perspective view and a plan view of a rectifying body, respectively, for explaining the rectifying body.

FIG. 7 is a schematic cross-sectional view seen from the inside of the barrel for explaining the action of the rectifying body.

FIG. 8 is a diagram showing a thermal shock test result and showing a relationship between a solder melting temperature and a thermal crack occurrence rate.

[Explanation of symbols]

 21 ... Barrel plating device 22 ... Barrel body 23, 24 ... End face material 25 ... Barrel 26, 27 ... Cathode wire 26a, 27a ... Introducing part 26b, 27b ... Bending part 26c, 27c ... Tip part 30, 31 ... Rectifier 32 ... Plating solution 33 ... Electronic parts 34 ... Media

Claims (2)

[Claims] 1. An electronic component and a medium for assisting electrical conduction between the barrel and the electronic component are placed in the barrel of a barrel plating apparatus, the barrel is immersed in a plating solution, and electricity is applied while rotating. In a method of manufacturing an electronic component having a step of forming an electrode film on the surface of an electronic component by plating, the barrel plating apparatus includes: a cylindrical barrel main body whose both ends are closed by a pair of end face materials; and a center of the end face material. From the tip end of the bent portion to the other end surface material side, the bent portion bent to extend to the side surface of the barrel at the tip of the introduced portion. A cathode wire arranged so as not to rotate together with the barrel body, and a barrel body and / or an inside of the end face material so as to extend from the vicinity of the center of the end face material to the tip side of the bent portion of the cathode wire. Characterized by using those having a rectifying member which is fixed to the end face material, manufacturing method of the electronic component. 2. A barrel plating apparatus for internally immersing an electronic component in a plating solution for plating, comprising: a barrel-shaped barrel main body whose both ends are closed by a pair of end face members; and a center of the end face member. An introductory part extended inward, a bent part bent at the tip of the introductory part so as to extend to the side surface side of the barrel, and a tip part extended from the tip of the bent part to the other end surface side. A cathode wire arranged so as not to rotate together with the barrel body, and a rectifying body provided inside the end face material of the barrel so as to extend from near the center of the end face material toward the tip of the bent portion of the cathode wire. A barrel plating apparatus, comprising: