JPH11350199A - Plating apparatus and plating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating apparatus which allows the omission of the replenishment of a plating liquid and the work for regulation of a liquid level, substantially prevents the occurrence of a fluctuation in the effective area of an anode and is capable of surely and efficiently forming plating films of consistent quality on many works. SOLUTION: This plating apparatus is constituted by erecting the bar-shaped anode 4 on the inside base surface 2a of a plating bath 2 in which the plating liquid 3 is stored. An annular basket 5 is pivotally supported at the anode 4 in such a manner that the basket may be rotated around the anode 4. A cathode ring 7 is stuck to the inside surface of the outer peripheral wall 5c of the basket 5. The basket 5 and the anode 4 are submerged in the plating liquid 3. Chip type electronic part elements 11 as the works are moved to the outer peripheral wall 5c side by rotationally driving the basket 5 around the anode 4, by which these elements are brought into contact with the cathode ring 7 and the plating films are formed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus and a plating method, for example, a plating method suitably used for forming a plating film as an external electrode layer on an outer surface of a chip type electronic component element such as a multilayer capacitor. The present invention relates to an apparatus and a plating method.

[0002]

2. Description of the Related Art In chip-type ceramic electronic components such as multilayer capacitors, external electrodes are formed on the outer surface of a ceramic sintered body. When this type of external electrode is formed by a plating method, a plating film may be formed on a base electrode formed by applying and baking a conductive paste for the purpose of further improving solderability. In such a case, various plating apparatuses have been conventionally proposed in order to efficiently form a plating film on the outer surfaces of many chip-type electronic component elements.

FIG. 4 is a sectional view showing an example of a conventional plating apparatus. In the plating device 51, a basket 53 is arranged in a container 52. The container 52 is provided for collecting the plating solution 54 discharged from the basket 53.

[0004] The basket 53 has a mesh wall 53b. The mesh wall 53b is provided so as to extend upward from the outer peripheral edge of the bottom plate 53a, and is formed of a mesh. A cathode ring 53c is fixed above the mesh wall 53b. An outer peripheral wall is constituted by the cathode ring 53c and the mesh wall 53b. A plating solution 54 is stored in the basket 53.

A vertically extending anode 55 is arranged at the center of the basket 53 so that the lower portion is immersed in the plating solution 54. When plating
In the basket 53, a large number of chip-type electronic component elements 56 are provided.
Is input. The chip-type electronic component element 56 has a structure in which external electrodes 56a and 56b are formed on both end surfaces thereof.
A plating film is formed on b.

That is, the plating solution 5 in the basket 53
The chip-type electronic component element 56 is put into the device 4, and the basket 53 is rotated around the anode. As a result, the chip-type electronic component element 56 is moved to the outer peripheral wall side by centrifugal force,
Contact is made with the cathode ring 53c, whereby a plating film is formed on the external electrodes 56a and 56b of the chip-type electronic component element 56.

[0007] The plating solution 54 flows out of the mesh wall 53 b and moves into the container 52. Therefore, it is necessary to replenish the discharged plating solution again. Therefore,
The plating solution discharged from the discharge port 52a of the container 52 is refilled into the basket 53 from a supply pipe 57 connected to the output side of the pump using a pump (not shown).

[0008]

In the plating apparatus 51, the plating solution 54 is discharged into the container 52 by centrifugal force due to the rotation of the basket 53. Therefore, the plating solution must be replenished into the basket 53 using a pump, and a mechanism for replenishing the plating solution such as a pump is required, and the apparatus is complicated.

In addition, it is necessary to control the amount of the plating solution to be replenished, and the operation is complicated. Further, since the plating solution 54 is repeatedly discharged and replenished from the basket 53 during plating, it is very difficult to control the level of the plating solution 54 in the basket 53 to a constant level.

Further, since the level of the plating solution 54 fluctuates, the effective area of the anode 55, that is, the area of the portion immersed in the plating solution 54 tends to change. for that reason,
There is a problem that the composition of the plating solution 54 in the basket 53 changes with time, and the quality of the formed plating film varies.

When the chip type electronic component element 56 is located at the center of the basket 53, no centrifugal force acts on the chip type electronic component element. Therefore, the chip-type electronic component element 56 is connected to the lower end of the anode 55 and the bottom plate 5 of the basket 53.
3a may not move to the outer peripheral side while being disposed. In such a case, no plating film is formed on the chip-type electronic component 56 that has not contacted the outer peripheral wall. That is, even if a large number of chip-type electronic component elements are put into the basket 53 and plated, there are not a few chip-type electronic component elements 56 from which no plating film is formed. did.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to simplify the structure and operation, to reliably form a plating film of a certain quality, and to apply to a large number of works. On the other hand, an object of the present invention is to provide a plating apparatus and a plating method capable of forming a plating film efficiently and reliably.

[0013]

According to a first aspect of the present invention, there is provided a plating apparatus comprising: a plating tank in which a plating solution is stored; and a plating tank buried in the plating tank in the plating tank. An anode fixed to the inner bottom surface of the plating tank, and a basket having a through hole through which the anode is inserted, and a basket supported by the anode so as to rotate about the anode, wherein the basket is provided. , A ring-shaped bottom,
An outer peripheral wall extending upward from an outer peripheral edge of the bottom, and an inner peripheral wall extending upward from an inner peripheral edge of the bottom to constitute an inner peripheral surface of the through hole; At least a part of the outer peripheral wall is formed of a porous member or a mesh so as to allow a plating solution to flow therethrough, and a cathode ring arranged on at least an inner peripheral surface of the outer peripheral wall of the basket, and the basket is arranged around the anode. A rotating drive means coupled to the basket for rotation.

According to the second aspect of the present invention, the cathode ring is disposed above an intermediate height of the inner peripheral surface of the outer peripheral wall of the basket, and the plating solution is provided below the lower edge of the cathode ring. The basket is configured to be able to flow out of the basket.

According to the third aspect of the present invention, the anode is made of a bar-shaped metal, and stands upright on the bottom of the plating tank. According to a fourth aspect of the present invention, there is provided a plating method using the plating apparatus according to any one of the first to third aspects, wherein a plurality of works are put into the basket, and the basket is placed in a plating solution. Forming a plating film on the outer surface of the work by rotating and driving the work around the anode to bring the work into contact with the cathode ring and moving the plating solution from inside the basket to outside the basket. .

According to the fifth aspect of the present invention, a chip-type electronic component element is used as a work, and an external electrode layer is formed by forming a plating film on an outer surface of the chip-type electronic component element.

[0017]

FIG. 1 is a schematic sectional view for explaining a plating apparatus according to one embodiment of the present invention.

In the plating apparatus 1, a plating solution 3 is stored in a plating tank 2. On the inner bottom surface 2a of the plating tank 2,
An anode 4 is fixed at the center. The anode 4 is arranged such that the upper end 4 a is located below the liquid level of the plating solution 3, that is, the anode 4 is buried in the plating solution 3. In this embodiment, the anode 4 is formed of a columnar member, and is provided upright on the inner bottom surface 2a.

The anode 4 can be made of an appropriate metal material that can function as an anode. At an intermediate height position of the anode 4, a basket 5 is supported so as to be rotatable around the anode 4. The step of rotatably supporting the basket 5 around the anode 4 is not particularly shown, but, for example, a ring-shaped stopper having a larger outer diameter than the anode 4 is fixed to the outer peripheral side surface of the anode 4. Can be configured so that the basket 5 is supported on the upper surface of the. Preferably, a bearing having a bearing or the like is fixed to an inner peripheral surface of a through hole of the basket 5 to be described later.
The rotation around the anode 4 may be smoothed.

The basket 5 has a substantially donut shape having a through hole 5a in the center, as shown in a perspective view in FIG. More specifically, the basket 5 has a ring-shaped bottom 5
b and an outer peripheral wall 5 extending upward from the outer peripheral edge of the bottom 5b
c, and an inner peripheral wall 5d extending upward from the inner peripheral edge of the bottom 5a to form the inner peripheral surface of the through hole 5a. The diameter of the through-hole 5a is substantially equal to the outer diameter of the anode 4, so that the basket 5 is configured to be able to smoothly rotate around the anode 4.

The inner peripheral wall 5d is preferably formed of a metal mesh as shown in the drawing, so that the plating solution can freely flow between the outer surface of the anode 4 and the inside of the basket 5. . The inner peripheral wall 5d may be formed of a porous member instead of the mesh. Further, the inner peripheral wall 5d may be formed of a normal member having no hole. Even in such a case, the plating solution 3 is in contact with the anode 4 outside the basket 5, and when the diameter of the through hole 5 a is larger than the diameter of the anode 4, the plating solution 3 contacts the inner peripheral surface of the through hole 5 a. Plating solution 3 between outer peripheral surface of anode 4
And the plating solution 3 is reliably brought into contact with the anode 4.

On the other hand, the outer peripheral wall 5c has a mesh wall 5e extending upward from the outer peripheral edge of the bottom portion 5b, and an annular wall 5f extending above the mesh wall 5e. Mesh wall 5e
Are configured so that the plating solution 3 in the basket 5 can be circulated. The mesh wall 5e may be constituted by a porous member.

A cathode ring 7 is fixed to the inner peripheral surface of the annular wall 5f. The cathode ring 7 is made of an appropriate metal according to the metal constituting the plating film.
In the present embodiment, the cathode ring 7 is arranged so as not to reach the upper end of the annular wall 5f, but the cathode ring 7 may be attached so as to cover the entire inner peripheral surface of the annular wall 5f. .

Returning to FIG. 1, in the plating apparatus 1, the basket 5 is supported by the anode 4 as described above, and is rotatable around the anode 4. Although not particularly shown, a connecting mechanism for rotating and driving the basket 5 is connected to the outer peripheral wall of the basket 5, and the connecting mechanism is connected to a motor M as a rotary driving source schematically shown. ing. That is, the basket 5 can be rotated around the anode 4 by rotating and driving the motor M.

With respect to the connection mechanism between the motor M and the basket 5, a pulley connected so as to be able to transmit a rotational driving force by a rotating shaft of the motor and a belt is arranged, and the rotational force of the pulley is transmitted to the basket 5. A structure in which the basket 5 is driven to rotate by transmitting it to a roller pressed against the outer surface of the outer peripheral wall 5c, or a gear is provided so as to be able to rotate together with the rotating roller pressed against the outer peripheral surface of the basket 5, and the gear is rotated by a motor. It is possible to employ an appropriate connection mechanism capable of transmitting the conventional rotational driving force, such as a structure in which the rotational driving force of the motor M is coupled to the gear mounted on the shaft via at least one gear and transmitted to the basket 5. it can.

Next, the operation and effect of the present invention will be clarified by specifically describing a plating method using the plating apparatus 1 of the present embodiment. In this embodiment, the basket 5
The chip-type electronic component element 11 shown in FIG. 2 is used as a work put into the inside. Chip type electronic component element 11
, Which constitutes a multilayer capacitor, has internal electrodes 13a to 13d arranged inside a ceramic sintered body 12 with a ceramic layer interposed therebetween. Internal electrode 1
3a and 13c are extended to the end face 12a, and the internal electrodes 13b and 13d are extended to the end face 12b.
External electrodes 14 and 15 are formed so as to cover the end faces 12a and 12b, respectively. The external electrodes 14 and 15 are
It is formed by applying and baking an Ag paste.

In this embodiment, a Ni plating layer is formed on the external electrodes 14 and 15 to prevent the external electrodes 14 and 15 from being eroded by solder. At the time of plating, first, a nickel plating bath such as a Watt bath is stored as a plating solution 3 in the plating tank 2. In this case, the plating liquid 3 is stored such that the liquid level of the plating liquid 3 is higher than the upper end 4 a of the anode 4. That is, the anode 4 is buried in the plating solution 3. Therefore, the contact area of the anode 4 with the plating solution 3, that is, the effective area does not change.

Next, a number of chip-type electronic component elements 11 are put into the basket 5, and the basket 5 is driven to rotate around the anode 4 as shown by the arrow in the figure. This rotation may be performed clockwise around the anode 4 as viewed from above, or may be rotated counterclockwise. Preferably, in order to prevent the plating film from adhering to the cathode ring 7 and the chip components from adhering to the cathode, it is desirable to alternately rotate clockwise and counterclockwise.

By rotating the basket 5 as described above, the chip-type electronic component 1
1 moves toward the outer peripheral wall 5 c and comes into contact with the cathode ring 7.
Therefore, a Ni plating film is formed on the external electrodes 14 and 15 of the electronic component element 11.

In this case, as described above, since the anode 4 is always buried in the plating solution 3, the effective area of the anode 4 does not change. Therefore, a plating film of a certain quality can be reliably formed on the external electrodes 14 and 15 of the electronic component element 11. Moreover, since the basket 5 and the anode 4 are buried in the plating solution 3, the plating solution 3 is replenished even if the plating solution 3 is discharged from the inside of the basket 5 to the outside of the basket 5 through the mesh wall 5e of the outer peripheral wall 5c. do not have to. Accordingly, a complicated operation for controlling the level of the plating solution 3 at a constant level can be omitted, and a complicated mechanism for replenishing the plating solution such as a pump, which is conventionally required, is not required.

Further, since the chip-type electronic component elements 11 are arranged outside the inner peripheral wall 5d, all the chip-type electronic component elements 11 receive centrifugal force due to rotation. Therefore, all the chip-type electronic component elements 11 are moved to the outer peripheral wall 5d side, and a plating film can be reliably formed on all of the supplied chip-type electronic component elements 11.

As described above, a Ni plating film can be formed on the external electrodes 14 and 15. Further, the chip-type electronic component element 11 is mounted in a second plating apparatus configured in the same manner as the plating apparatus 1 except that the plating solution 3 and the cathode ring 7 are configured to form a Sn plating film. By injecting, the Sn plating film can be formed on the Ni plating film. In this way, the Ni plating film as the solder erosion prevention layer is formed on the external electrodes 14 and 1.
After the formation of No. 5, an Sn plating layer for improving the solderability can be efficiently formed.

In the above embodiment, the chip type electronic component element 1
Although a multilayer capacitor is illustrated as the example 1, it can be widely used for forming a plating film on an external electrode of a chip-type electronic component element other than the multilayer capacitor. In addition to the purpose of forming a plating film on the external electrode of the chip-type electronic component element, the external electrode itself may be formed directly on the element surface by the above-described plating method.

In addition, the present invention can be used for forming a plating film on a large number of relatively small works as described above. It can be widely used for forming a plating film on the outer surface of the device, and can be suitably used, for example, for forming a plating film on a ball-shaped component or a metal terminal component.

Although the anode 4 is made of a rod-shaped metal in the above embodiment, the rod-shaped anode 4 is formed by laminating a metal film constituting the anode on the surface of a rod made of an insulating material other than metal. It may be composed of a bonded or bonded product.

[0036]

In the plating apparatus according to the first aspect of the present invention, since the basket and the anode are buried in the plating solution, the effective area of the anode during plating hardly fluctuates.
Therefore, a plating film of a certain quality can be reliably formed on the outer surface of the work.

Although the plating solution can flow between the inside and outside of the basket, the anode and the basket are buried in the plating solution, and the plating solution is not discharged out of the plating tank. Therefore, since there is no need to replenish the plating solution, a complicated mechanism for replenishing the plating solution such as a pump can be omitted, and a complicated operation for controlling the level of the plating solution can be omitted. Can be.

Further, a through hole is formed at the center of the basket 5, and the work is arranged on the ring-shaped bottom between the inner peripheral wall and the outer peripheral wall of the basket. , Centrifugal force acts on all the workpieces. Therefore, all the workpieces can be moved to the outer peripheral wall side, so that all the workpieces can be almost certainly brought into contact with the cathode ring, and the plating films can be reliably formed on these workpieces.

Therefore, by using the plating apparatus according to the present invention, a plating film of a constant quality can be reliably and easily formed on the outer surfaces of a large number of works without the need for complicated level adjustment of the plating solution. It can be formed efficiently.

In the plating apparatus according to the second aspect of the present invention, the cathode ring is attached above the intermediate height position of the inner peripheral surface of the outer peripheral wall, and the plating is performed below the lower edge of the ring-shaped cathode. The liquid flows out of the basket out of the basket. Further, since it is only necessary to attach the cathode ring to the inner peripheral surface of the outer peripheral wall, the outer peripheral wall having a function as a cathode and a function of allowing the plating solution to flow out of the basket can be realized with a relatively simple configuration. it can.

According to the third aspect of the present invention, the anode is made of a bar-shaped metal, and the anode is provided upright on the bottom of the plating tank. Therefore, the anode can be easily formed simply by fixing the rod-shaped metal on the bottom surface of the plating tank.

According to a fourth aspect of the present invention, there is provided a plating method according to any one of the first to third aspects, wherein a plurality of works are put into a basket and the basket is rotated around an anode. Then, by simply bringing the workpiece into contact with the cathode ring and moving the plating solution from the inside of the basket to the outside of the basket, a plating film of a constant quality can be efficiently formed on the outer surface of the workpiece. In addition, as described above, since the operation of adjusting the level of the plating solution is not required, the operation management when forming the plating film can be simplified.

According to the fifth aspect of the present invention, a chip-type electronic component element is used as a work, and an external electrode layer is formed by forming a plating film on an outer surface of the chip-type electronic component element. In this case, the chip-type electronic component element
In the basket, the basket is reliably moved to the outer peripheral wall side by the rotational drive of the basket, and comes into contact with the cathode ring. Therefore, it is possible to reliably and easily form a plating film of a constant quality on the outer surfaces of many chip-type electronic component elements as described above.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a plating apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a chip-type electronic component element as a work on which a plating film is formed in one embodiment of the present invention.

FIG. 3 is a perspective view for explaining a basket used in the plating apparatus of the embodiment shown in FIG. 1;

FIG. 4 is a schematic sectional view for explaining an example of a conventional plating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Plating apparatus 2 ... Plating tank 2a ... Inner bottom surface of plating tank 3 ... Plating solution 4 ... Anode 4a ... Top end of anode 5 ... Basket 5a ... Through hole 5b ... Ring-shaped bottom 5c ... Outer peripheral wall 5d ... Inner peripheral wall 5e ... Mesh Wall 5f: annular wall 7: cathode ring 11: chip-type electronic component element

Claims (5)

[Claims] 1. A plating tank in which a plating solution is stored, an anode disposed so as to be buried in the plating solution in the plating tank, and fixed to a bottom surface in the plating tank; A basket supported by the anode so as to rotate about the anode, wherein the basket extends upward from a ring-shaped bottom and an outer peripheral edge of the bottom. An outer peripheral wall, and an inner peripheral wall extending upward from an inner peripheral edge of a bottom portion to form an inner peripheral surface of the through hole, and at least a part of the inner peripheral wall and the outer peripheral wall circulate a plating solution. A cathode ring arranged on at least the inner peripheral surface of the outer peripheral wall of the basket, and connected to the basket to rotate the basket around the anode. Characterized in that it comprises a rotary drive means, the plating apparatus. 2. The cathode ring is disposed above an intermediate height of an inner peripheral surface of an outer peripheral wall of the basket, and a plating solution flows from inside the basket to outside the basket below a lower edge of the cathode ring. The plating apparatus according to claim 1, wherein the plating apparatus is configured to be able to flow out. 3. The plating apparatus according to claim 1, wherein the anode is made of a bar-shaped metal, and is erected on the bottom surface of the plating tank. 4. A plating method using the plating apparatus according to claim 1, wherein a plurality of workpieces are put into the basket, and the basket is placed around a positive electrode in a plating solution. A step of forming a plating film on the outer surface of the work by rotating and driving the work to contact the cathode ring and moving the plating solution from inside the basket to outside the basket. 5. An external electrode layer is formed by using a chip-type electronic component element as the work and forming a plating film on an outer surface of the chip-type electronic component element.
The plating method described in 1.