JPH07180093A - Barrel plating method - Google Patents

Abstract

PURPOSE:To improve the contact efficiency of objects to be plated and a plating liquid and to form plating films having a uniform thickness by carrying out operations to rotate a barrel housing the objects to be plated in the plating liquid, then to pull up the barrel, to rotate the barrel in air and to rotate the barrel again in the plating liquid. CONSTITUTION:The many objects 4 to be plated are housed in the barrel 1 consisting of a wire net or the like disposed with a negative electrode and are immersed into the plating liquid 3 in a plating tank 2 disposed with a positive electrode. Electroplating is executed by energizing the barrel and plating liquid, and bringing the objects 4 to be plated and the plating liquid 3 into contact with each other while rotating the barrel 1. The energization is stopped after the prescribed time and the barrel 1 is pulled up into the air and is rotated; thereafter, the barrel 1 is again immersed into the plating liquid 3 and the electroplating is executed by rotating the barrel 1 while energizing the barrel and plating liquid. Such operations are carried out at least once or over, by which the contact efficiency of the objects 4 to be plated and the plating liquid 3 and the plating films having the uniform thickness are formed on the objects 4 to be plated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating method,
More specifically, the present invention relates to a barrel plating method in which a barrel containing an object to be plated such as an electronic component is rotated in a plating solution and the object to be plated and the plating solution are brought into contact with each other to plate the object to be plated.

[0002]

2. Description of the Related Art FIG. 3 is a view showing a conventional barrel plating method for electronic parts.

That is, in this barrel plating method, a large number of objects to be plated (for example, electronic parts such as monolithic ceramic capacitors) 4 are housed in a barrel 1 at least a part of which is made of a material such as a wire mesh through which a plating solution passes. After doing
The object to be plated 4 is immersed in the plating solution 3 in the plating tank 2 and the barrel 1 is rotated in the plating solution 3 to bring the object to be plated 4 and the plating solution 3 into contact with each other to perform a predetermined plating on the object to be plated 4. .

[0004]

However, in the above-mentioned conventional barrel plating method, the object 4 to be plated is brought into contact with the plating solution 3 by rotating the barrel 1, but the object 4 to be plated is small. Then, it becomes difficult to bring the object 4 to be plated and the plating solution 3 into sufficient contact with each other.

As a result, it becomes difficult to form a plated coating having a uniform thickness, the variation (CV) in the thickness of the plated coating increases to, for example, 25%, and the distribution of the thickness of the plated coating increases, for example. As shown in FIGS. 4 and 5, the tail distribution (FIG. 4) or the two-peak distribution (FIG. 5) is formed, and it becomes impossible to secure desired quality in terms of plating film characteristics and the like.

The above problem is a problem that occurs regardless of whether electrolytic plating is used or electroless plating is used.

The present invention solves the above-mentioned problems, and improves the contact efficiency between the object to be plated in the barrel and the plating solution to form a plating film having a uniform thickness. The purpose is to provide.

[0008]

To achieve the above object, the barrel plating method of the present invention comprises rotating a barrel containing an object to be plated in a plating solution and bringing the object to be plated into contact with the plating solution. In the barrel plating method of plating the object to be plated with, during the plating process performed by rotating the barrel in the plating solution, the barrel is pulled up from the plating solution and rotated, and then immersed in the plating solution again and rotated. The pulling / rotating operation is performed at least once.

[0009]

[Function] During the plating process performed by rotating the barrel in the plating solution, the barrel is pulled up from the plating solution and rotated, and then the barrel is immersed in the plating solution again and rotated to perform pulling and rotating operations. As the plating liquid falls from the barrel and the barrel rotates while being pulled up from the plating liquid, the liquid runs out better, and the plating liquid is renewed by immersing the barrel again. By rotating the barrel in the state of being pulled up from above, the rolling state (stirring state) of the object to be plated in the barrel changes and the object to be plated sufficiently rolls, so the barrel is immersed in the plating solution again. When it is rotated, for example, the parts that were not in contact with the plating solution before the pulling / rotating operation come into contact with the plating solution. And it improves the contact efficiency with the plating liquid,
It becomes possible to form a plating film having a uniform thickness.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a barrel plating method of the present invention.

In this embodiment, an object to be plated is placed in a barrel 1 made of a material such as a wire mesh, through which a plating solution passes, in which a (-) electrode (not shown) is provided. A large number of objects to be plated (multilayer ceramic capacitors in this embodiment) 4 and a large number of contact media (for example, S
After accommodating a small ball (not shown) made of a conductive metal such as US, the barrel 1 is dipped in a plating solution 3 in a plating tank 2 in which a (+) electrode (not shown) is arranged, By rotating the barrel 1 in the plating solution 3, the plating object 4 and the plating solution 3 are brought into contact with each other, and plating is performed on a predetermined position of the plating object 4 (in this embodiment, the surface of the external electrode of the multilayer ceramic capacitor). Was applied. Hereinafter, the plating process of this embodiment will be described.

First, the barrel 1 containing the object to be plated 4 and the contact medium is dipped in the plating solution 3 to obtain (+) and (-).
Electroplating is performed by rotating the barrel 1 at a rotation speed of, for example, about 6 times / minute while energizing between the electrodes. After rotating the barrel 1 for about 10 minutes, the energization is stopped, the barrel 1 is pulled out of the plating solution 3, and is rotated in the air at a rotation speed of, for example, about 3 times / minute for 1 minute. Then, the barrel 1 is immersed in the plating solution 3 again, and while the electrodes are energized, the barrel 1 is rotated at a rotation speed of about 6 times / minute to perform electrolytic plating. Thereafter, the above-mentioned operations (pulling / rotating operation) are repeated to form a predetermined plating film on the object 4 to be plated.

According to the method of the above embodiment, the operation of (, pulling / rotating operation) was performed 4 times and the size was 1.6 mm ×
When the external electrodes (not shown) of a 0.8 mm x 0.8 mm monolithic ceramic capacitor were plated, the rate of occurrence of defective products that did not have a plating film of a specified thickness was measured by the conventional barrel plating method. It could be reduced to 1/10 or less of the case.

Further, the variation in the thickness of the plating film (C
V) is reduced to 15% or less, and the distribution curve of the thickness shows the tail distribution (FIG. 4) and the double peak distribution (FIG. 5) observed in the conventional barrel plating method as shown in FIG. It was confirmed that there was no normal distribution curve.

Further, in the above embodiment, the case where the interval for pulling up the barrel from the plating solution was set to 10 minutes was explained, but in the barrel plating method of the present invention, the interval for pulling up the barrel from the plating solution is limited to this. It is not something that will be done. Therefore, the interval for pulling up the barrel from the plating solution can be set to less than 10 minutes or more than 10 minutes, but usually it is set to 1/3 to 1/10 of the total plating time. preferable.

In the above embodiment, the case where the barrel pulled up from the plating solution is rotated in the air for 1 minute has been described, but in the barrel plating method of the present invention,
The time for rotating the barrel pulled out from the plating solution in the air is usually preferably in the range of 1/10 to 1/50 of the total plating time. However, the present invention is not limited to this, and it may be set outside this range.

Further, in the above embodiment, the rotation speed of the barrel in the plating solution and that in the air are 6 times /
However, the barrel rotation speed is usually 3 to 10 times / minute in the plating solution.
In the minute and air, the range of 1 to 5 times / minute is preferable. However,
The present invention is not limited to this, and it is possible to set it outside this range, and it is not necessary to make the respective rotation speeds in the plating solution and the air all the same every time.

In the above embodiment, the case where the number of pulling / rotating operations performed during one plating treatment was set to 4 times was described, but it is usually preferable to set it to 2 to 10 times. However, the present invention is not limited to this, and it may be set outside this range.

Further, there is no particular limitation on the time of one plating treatment (total process time), but it is usually 10 to 100.
It is preferable to set it as minutes.

In the above embodiment, the case where the laminated ceramic capacitor is plated has been described, but the object to be plated by the barrel plating method of the present invention is not limited to this, and the ceramic filter is not limited to this. It can be applied when plating various electronic components such as semiconductor elements, piezoelectric elements, resonators, and thermistor elements having positive or negative characteristics.

Further, in the above embodiment, the case where the electrolytic plating is performed has been described, but the barrel plating method of the present invention can be applied not only to the case of electrolytic plating but also to the case of electroless plating. In that case, the same effect as that of the above embodiment can be obtained.

The barrel plating method of the present invention is not limited to the above-mentioned embodiments in other points as well, and the type of metal to be plated, the plating conditions such as the composition and temperature of the plating solution, and the specific barrel. With regard to the shape and the like, various applications and modifications can be made within the scope of the invention.

[0023]

As described above, according to the barrel plating method of the present invention, the barrel is pulled up from the plating solution and rotated during the plating process performed by rotating the barrel in the plating solution, and then the plating solution is again prepared. Since the pulling / rotating operation of immersing in and rotating it at least once is performed,
It is possible to improve the contact efficiency between the object to be plated in the barrel and the plating solution, and to reliably form a plating film having a uniform thickness.

[Brief description of drawings]

FIG. 1 is a diagram showing a barrel plating method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a distribution curve of the thickness of the plating film formed by the barrel plating method according to the embodiment of the present invention.

FIG. 3 is a diagram showing a conventional barrel plating method.

FIG. 4 is a diagram showing a distribution curve of the thickness of a plating film formed by a conventional barrel plating method.

FIG. 5 is a diagram showing a distribution curve of the thickness of a plating film formed by a conventional barrel plating method.

[Explanation of symbols]

1 barrel 2 plating tank 3 plating solution 4 object to be plated (multilayer ceramic capacitor)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobushige Moriwaki, Inventor No. 26-10 Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor, Kazuhide Moriyoshi No. 26-10 Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Kenichi Ito 2 26-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A barrel plating method in which a barrel containing an object to be plated is rotated in a plating solution and the object to be plated is brought into contact with the plating solution to rotate the barrel in the plating solution. In the middle of the plating process performed by pulling the barrel out of the plating solution and rotating it,
A barrel plating method characterized in that the pulling / rotating operation of immersing in a plating solution again and rotating is performed at least once.