JPH01310531A - Method and jig for forming electrode of electronic component - Google Patents

Abstract

PURPOSE:To contrive improvement in an electrode forming treatment and the reduction in cost of electronic components by a method wherein the main bodies of electronic components are inserted into the through holes, the inner circumferential part of which is formed by water-expandable rubber, of a tabular jig, the end part of the main body is retained in an exposed state, and the electronic component main body is dipped into a plating bath in the state wherein the water-expansible rubber is expanded. CONSTITUTION:A tabular jig 11, consisting of water-expandable rubber 2 on the circumferential part which regulates at least the inner circumferential surface of through holes 14 and having a plurality of through holes 14, is prepared. The main bodies 15 of the electronic components are inserted into the through holes 14, and the main bodies 15 of the electronic components are retained by the jig 11 in the state wherein their end face is exposed. Then, the electronic component main bodies are brought into the state wherein they are pressed by the expanded water-expandable rubber 12, and the electronic component main bodies 15 retained by the jig 11 are dipped into a plating bath. Accordingly, the water-expandable rubber 12 can be put in the state wherein the water-expandable rubber 12 is closely fixed to the region on which a plated film is not formed. As a result, the improvement in efficiency of electrode forming treatment and the reduction in cost of the electronic components can be achieved.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for forming electrodes and a jig for forming electrodes for electronic components such as capacitors, resistors, varistors, and inductors, and particularly relates to electroless plating. The aim is to improve the efficiency of forming electrodes on a large number of electronic components.

More specifically, the present invention relates to a technique for forming electrodes of electronic components having a body made of ceramic.

[Conventional technology] For example, when manufacturing a multilayer ceramic capacitor,
First, a main body 1 as shown in FIG. 16 is prepared. The main body 1 includes a dielectric body 2 made of a ceramic laminated structure, and a plurality of internal electrodes 3 are formed inside the dielectric body 2 . The internal electrodes 3 are formed so as to be exposed alternately on opposing end surfaces of the dielectric 2. Then, as shown in FIG. 17, when a pair of external electrodes 4 are formed on the end face of the dielectric 2, the external electrodes 4 are electrically connected to a specific internal electrode 3. . In this way, a multilayer ceramic capacitor 5 is obtained.

The above-mentioned external electrodes 4 are usually formed by printing a conductive paste containing silver or silver/palladium, and then performing a baking process. However, forming the external electrodes 4 by such a method has problems such as being relatively inefficient and unsuitable for mass processing.

Therefore, a method of forming external electrodes by electroless plating has been proposed as a method particularly suitable for mass processing. This method is described, for example, in Japanese Patent Application Laid-Open No. 55-63817. Electroless plating typically involves sensitization, activation,
For example, if such electroless plating is applied to the main body 11 shown in FIG. 16 without taking any steps, , an electroless plating film is formed on the entire outer surface of the main body 11. Therefore, in order to form the external electrode 4 as shown in FIG. 17 by electroless plating, an etching process must be performed so that the plating film is formed only in a specific area.

Specifically, an etching resist is formed on both ends of the main body l on which a plating film has been formed, and then it is immersed in an etching solution, thereby removing the plating film in unnecessary areas, and then removing the etching resist. things are being done.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology has a problem in that the number of steps increases because etching treatment is required.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a method for forming electrodes for electronic components and a jig for forming electrodes, which can advantageously solve the above-mentioned conventional problems.

[Means for Solving the Problems] A method for forming electrodes of electronic components according to the present invention is directed to a method of forming electrodes of electronic components by electroless plating, and in order to solve the above-mentioned technical problems. , is characterized by the following steps. That is, a step of preparing a plate-shaped jig having a plurality of through holes and at least a peripheral portion defining an inner circumferential surface of the through holes is made of water-swellable rubber; inserting the component body and holding the electronic component body with the jig with its end surface exposed; and expanding the water-swellable rubber so that the water-swellable rubber covers the electronic component body. A method for forming an electrode of an electronic component, comprising: bringing the water-expandable rubber into a compressed state; and immersing the electronic component main body held by the jig in a plating bath while the water-expandable rubber is expanded. It is.

Further, according to the present invention, there is provided an electrode forming jig that is advantageously used in the above-described electrode forming method. This jig has a plate shape as a whole, and is for receiving the electronic component main body with its end surface exposed, and at least the peripheral part defining the inner peripheral surface thereof is made of water-swellable rubber. The device further includes a member having a plurality of through holes and regulating the direction of expansion of the water-swellable rubber so that it is directed toward the center of the through holes.

[Operations and Effects of the Invention] In the electrode forming method of the present invention, when the water-swellable rubber is expanded by, for example, bringing water into contact with the water-swellable rubber, the water-swellable rubber compresses electronic components. become a state. Therefore, the water-swellable rubber is suitable for the main body of electronic components.
It can be brought into close contact with areas where it is not desired to form a plating film.

If the electronic component is immersed in a plating bath in this state, a plating film will be formed on the surface of the electronic component body, except for the area in contact with the water-swellable rubber.

Therefore, the steps of forming an etching resist, performing etching treatment, and removing the etching resist are no longer necessary, and a plating film can be easily formed in a specific region. Therefore, formation of electrodes by plating can be completed in a short time.

In addition, the jig has a plurality of through-holes for receiving electronic component bodies, so electrodes can be formed on a large number of electronic components at once, and the electrode formation process can be easily performed. It becomes more efficient, and as a result, it is possible to reduce the cost of electronic components.

Furthermore, since plating can be performed on a plurality of electronic component bodies at the same time, electrodes can be formed without variations among the plurality of electronic components.

[Example] FIG. 1 shows a plan view of an electrode forming jig 1 used in an example of the present invention. Jig 11
has a plate shape as a whole, and the water-swellable rubber part 1
2 and an outer frame 13 surrounding the periphery. The water-swellable rubber constituting the water-swellable rubber portion 12 may be a synthetic rubber that is specially modified so that its hydrophilic portion undergoes hydrogen bonding with water molecules, resulting in self-volume expansion, or a water-swellable resin and chloroprene. There are also mixtures of non-expandable materials and expansible rubber, such as commercially available unvulcanized butyl rubber sealants, composite butyl rubber sealants, and vulcanized rubber sealants. Rubber-based sealing materials, tar/urethane-based sealing materials, etc. can be used.

A plurality of through holes 14 are formed in the water-swellable rubber portion 12 . As shown in FIG. 2, the through hole 14 receives an electronic component body 15 to be plated.

The main body 15 inserted into the through hole 14 has both end surfaces exposed.

Next, using the jig 11 shown in FIGS. 1 and 2,
A method for forming electrodes on both end surfaces of the electronic component body 15 will be described.

First, a main body 15 corresponding to the main body 1 for the multilayer ceramic capacitor shown in FIG. 16 described above, for example, is prepared. Next, the main body 15 is sequentially subjected to degreasing, sensitization, and activation treatments.

Next, as shown in FIG. 2, the main body 15 is inserted into each through hole 14 provided in the jig 11.

The size of the through hole 14 is selected so that it can hold the main body 15 when received in this manner.

When the main body 15 is held by the jig 11, both end surfaces thereof are exposed from the jig 11.

Next, the jig 11 is immersed in water while holding the main body 15. As a result, the water-swellable rubber portion 12 is swollen with water. This swelling appears as self-volume expansion of the water-swellable rubber constituting the water-swellable rubber portion 12, but since the water-swellable rubber portion 12 is surrounded by an outer frame 13 that does not expand with water, water-swellable rubber The outward expansion of the rubber is regulated by the outer frame 13, and therefore,
This appears as a force that compresses the body 15 received within the through hole 14. Therefore, the inner circumferential surface defining the through hole 14 is in close contact with the main body 15.

Next, the main body 15 held by the jig 11 is immersed in the plating bath while maintaining the above-mentioned state. As a result, a plating film is formed only on both ends of the main body 15 exposed from the jig 11.

This plating film constitutes the external electrode 4 shown in FIG. 17 mentioned above.

Next, the main body 15 is taken out from the jig 11.

At this time, if the water-swellable rubber portion 12 is dried, it will shrink, and the main body 15 can be easily removed from the through hole 14.

Although the through hole 14 shown in FIG. 1 had a circular cross-sectional shape, the cross-sectional shape of the through hole is arbitrary.

For example, it may be a square as shown in FIG. 3, a rectangle as shown in FIG. 4, a hexagon as shown in FIG. 5, a triangle as shown in FIG. 6, or the like.

The shape of the through hole may be changed depending on the shape of the electronic component body to be inserted therein. However, the cross-sectional shape of the through hole is
It is not necessarily necessary to have a shape similar to the cross-sectional shape of the electronic component body inserted therein. This is because the inner peripheral surface of the through hole is defined by easily changeable water-swellable rubber, so the through hole has a relatively large tolerance for the shape of the electronic component inserted therein. be.

FIG. 7 shows another example of the longitudinal cross-sectional shape of the through hole. Tapers 16 and 17 that open outward are formed at both ends of the through hole 14a shown in FIG. By forming the tapers 16 and 17 in this way, it becomes easier to insert the electronic component body into the through hole 14a, and it also becomes easier to take it out.

FIG. 8 shows a jig 11a as yet another embodiment of the invention. The jig 11a shown in FIG.
In addition to the outer frame 13a, a member that regulates the direction of expansion of the water-swellable rubber portion 12a that forms the through-hole 14 is directed toward the center of the through-hole 14. A lattice member 18 is provided.

Therefore, the water-swellable rubber portion 12a
1 (
ll! Through-holes 14 are formed. According to this embodiment, the expansion action of the water-swellable rubber portion 12a can be applied in the direction of shrinking the through-holes 14 more efficiently and with almost no difference between the through-holes 14.

FIG. 9 shows a jig 11b as yet another embodiment of the invention. The jig 11b aligns the direction of expansion of the water-swellable rubber portion 12b in which the through-hole 14 is formed with the through-hole 1.
A plate-shaped holding member 19 is provided as a member for regulating the direction toward the center of 4.

In other words, a circular hole is formed in the holding member 19, and the ring-shaped water-swellable rubber portion 12 is formed in the holding member 19.
b is fitted. According to this embodiment, the water-swellable rubber portion 12b forms only the peripheral portion that defines the inner circumferential surface of the through hole 14, so that the water-swellable rubber portion 12b is more effective than the embodiment shown in FIG. can be exerted in the direction of shrinking the through hole 14.

FIG. 10 shows a sectional view of a part of a jig 11c as yet another embodiment of the invention.

In this jig 11C, the water-swellable rubber portion 12C is not only surrounded on its outer periphery by the outer frame 13c, but also sandwiched between the two fixing plates 20 and 21 from above and below. Therefore, the expansion of the water-swellable rubber portion 12c in the thickness direction is regulated by the fixing plate 20.21, so that when the water-swellable rubber portion 12c expands, the through hole 14a can be further contracted. .

In addition, the fixing 11i20.21 is the water-swellable rubber part 1,
2c is intended to reduce the area that comes into contact with water, so in order to eliminate this inconvenience, the fixing plate 20.21 is formed with a large number of through holes, for example, as shown by through holes 22 and 2B. It is preferable to leave it there.

Note that instead of forming such through holes 22.23, the fixed plate 20.21 may be made of a porous material.

The shape of the electronic component main body to which this invention is applied is arbitrary. That is, any shape can be applied as long as electrodes are formed on the end face of the electronic component body. That is, a rectangular parallelepiped shape as shown in FIG. 11, a cylindrical shape as shown in FIG.
For electronic component bodies of any shape, such as cylindrical as shown in Figure 3, disc-shaped as shown in Figure 14, or square plate-shaped as shown in Figure 15. , this invention can be applied.

In addition, in the electrode forming method according to the present invention, the step of holding the electronic component main body in the jig is a step of degreasing, in addition to the step of completing the degreasing, sensitization, and activation treatments, as described above. It may be a stage of sensitization, or a stage of activation.

Furthermore, when an aqueous solution is used in the sensitization and activation treatments, the water-swellable rubber may be swollen with water contained in the aqueous solution. In other words, the step of expanding the water-swellable rubber may also be performed as a sensitization treatment or an activation treatment.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an electrode forming jig 11 as an embodiment of the present invention. FIG. 2 is a sectional view showing a state in which the electronic component body 15 is held by the jig 11 shown in FIG. FIG. 3, FIG. 4, FIG. 5, and FIG. 6 each show other examples of the cross-sectional shape of the through hole. FIG. 7 is a longitudinal sectional view of a through hole 14a formed in an electrode forming jig as another embodiment of the present invention. FIG. 8 is a plan view showing an electrode forming jig 11a as still another embodiment of the present invention. FIG. 9 is a plan view of an electrode forming jig 11b as still another embodiment of the present invention. FIG. 10 is a sectional view of an electrode forming jig 11C as still another embodiment of the present invention. Figures 11, 12, 13, 14 and 15
The figures are perspective views showing various examples of the shapes of electronic component bodies to which the present invention is applied. FIG. 16 is a sectional view showing the main body l of the multilayer ceramic capacitor. FIG. 17 is a sectional view showing a multilayer ceramic capacitor 5 obtained by forming an external electrode 4 on the main body 1 shown in FIG. 16. In the figure, 1.15 is the electronic component body, 4 is the external electrode (
electrode), 5 is a multilayer ceramic capacitor (electronic component),
11. lla, llb, llc are electrode forming jigs, 12
．． 12 a, 12 b, 12 c are water-swellable rubber parts, 13. 13 a, 13 c are outer frames (regulating members), 14. 14 ai, ti communication holes] 8 are lattice members (regulating members), 19 is a holding Member (regulating member), 20.
21 is a fixing plate (regulating member). Figure 3 Figure 4 Figure S Figure 6

Claims (2)

[Claims] (1) A method for forming electrodes of electronic components by electroless plating, the method comprising a plurality of through holes, and at least a peripheral portion defining an inner circumferential surface of the through holes is made of water-swellable rubber. preparing a plate-shaped jig; inserting the electronic component body into the through hole and holding the electronic component body with the jig with its end surface exposed; and the water-swellable rubber. plating the electronic component body held by the jig while the water-expandable rubber is expanded, thereby causing the water-expandable rubber to press against the electronic component body; A method for forming an electrode of an electronic component, comprising: immersing it in a bath. (2) A plurality of units having a plate shape as a whole, for receiving the electronic component body with its end surface exposed, and at least the peripheral portion defining the inner peripheral surface thereof is made of water-swellable rubber. What is claimed is: 1. A jig for forming an electrode of an electronic component, the jig having a through hole, and further comprising a member for regulating the direction of expansion of the water-swellable rubber so that it is directed toward the center of the through hole.