JPH06179976A - Chemical plating vessel - Google Patents

Abstract

PURPOSE:To prevent the generation of plating defect by providing an over flow chamber outside of a plating vessel and arranging a plating solution discharging pipe, a perforated straightening plate and an air discharging pipe successively from downward to upward at the bottom of the plating vessel to uniformize the flow rate and dispersion of the plating solution. CONSTITUTION:The over flow chamber 12 is provided outside of the plating vessel 11 and the plating solution discharging pipe 13 having a discharging opening 130, the perforated straightening plate 14 having a plating solution passing hole 140, the air discharging pipe 15 having an air discharging opening 150 are successively arranged from downward to upward at the bottom of the plating vessel 11. The plating solution 2 flowing out from the plating vessel 11 to the over flow chamber 12 is fed to the discharging pipe 13 through a filter 17 and a heat exchanger 18 and is discharged from the discharging opening 130. The discharged plating solution 2 is uniformized in flow rate and dispersion by the flowing opening 140 of the straightening plate 14, is stirred by air from an air discharging opening 150 and is uniformized in the distribution of dissolved oxygen content. As a result, the generation of plating defect in a material to be treated is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical plating tank in which the flow rate and dispersion of a plating solution are uniform and a plating failure does not occur on an object to be processed.

[0002]

2. Description of the Related Art As shown in FIGS. 6 and 7, a conventional chemical plating bath 9 is, for example, a workpiece 3 such as a printed wiring board.
There are some products that are chemically plated on the surface. The chemical plating tank 9 includes a plating tank 90 for containing the plating solution 2 and the object 3 to be treated, an air discharge pipe 91 disposed below the plating tank 90, a circulation pipe 92 for circulating the plating solution 2 and the circulation pipe 92. It is composed of a circulation pump 93 and a filter 94 provided in

A suction pipe 920 of the circulation pump 93.
Is connected to the plating solution discharge port 902 of the plating tank 90. The air discharge pipe 91 is connected to an air pump 912 connected via an air pipe 911. By this,
Bubbling of air is caused in the plating solution 2 to stir the plating solution 3. The circulation pipe 92 is a plating tank 90.
Are connected to the plating solution input ports 901 arranged at both upper ends of the. The plating solution 2 is constantly circulated and supplied in the plating tank 90.

[0004]

However, the above-mentioned conventional technique has the following problems. That is, in the plating tank 90, from both upper end portions of the plating solution inlet 901,
The plating solution 2 is supplied. Therefore, as shown in FIGS. 6 and 8, the air 914 rising from below the plating tank 90 is pushed back by the liquid flow 21 of the plating liquid 2.

Therefore, the flow of the air 914 becomes uneven. As a result, in the object 3 to be processed, plating defects such as uneven plating thickness occur. Further, the speed of the liquid flow 21 of the plating liquid 2 is high near the plating liquid input port 901, but the speed of the liquid flow 21 is low at the lower peripheral edge portion of the plating tank 90.

Therefore, the flow velocity of the plating solution 2 becomes uneven in each part of the plating tank 90. As a result, in the object 3 to be processed, the thickness of the plating film becomes thicker in the portion where the flow velocity is high. On the other hand, in the portion where the flow velocity of the plating liquid 2 is low, the thickness of the plating film becomes thin. As a result, in the object to be processed 3, plating defects such as uneven plating occur.

Further, since the position of the plating solution inlet 901 is above, unevenness in the flow rate of the plating solution 2 is likely to occur.
Therefore, as shown in FIG. 8, a stagnation area (dead zone) 22 of the plating solution 2 is formed in the vicinity of the lower peripheral portion of the plating tank 90. In the dead zone 22, since the flow velocity of the plating solution 2 is extremely low, the amount of dissolved oxygen (O ₂ ) is small. Therefore, defective plating of the object 3 is promoted.

Further, foreign matter is easily collected in the dead zone 22 due to the stay of the plating solution 2. Therefore, foreign matter may adhere to the workpiece 3 in the dead zone 22 to cause plating failure. The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a chemical plating tank in which the flow rate and the dispersion of the plating solution are uniform and the defective plating does not occur on the object to be processed.

[0009]

According to the present invention, there is provided a plating tank for containing a plating solution and an object to be treated, an overflow chamber provided outside the plating tank, and a plating solution discharge which is arranged below the plating tank in order from below to above. A pipe, a perforated straightening plate and an air discharge pipe, a circulation pipe for circulating the plating liquid flowing into the overflow chamber to the plating liquid discharge pipe, a circulation pump and a filter interposed in the circulation pipe, and the air discharge pipe The chemical plating bath is characterized by comprising an air pump connected to the above through an air pipe.

What is most noticeable in the present invention is that the chemical plating bath includes an overflow chamber provided outside the plating bath, a plating solution discharge pipe arranged below the overflow chamber in order from the bottom to the top, and a porous plate. It is to have a current plate and an air discharge pipe.

The overflow chamber is arranged at the entire peripheral portion of the plating tank or a part thereof. Further, the overflow chamber is connected to a circulation pipe for circulating the plating solution discharge pipe, and a circulation pump and a filter provided in the circulation pipe. A heat exchanger can also be connected as shown in the first embodiment.

The porous straightening plate has a large number of plating solution flow holes in order to make the flow rate and dispersion of the plating solution uniform.
The size and shape of the plating solution flow hole are not particularly limited, but it is preferably a round hole having a diameter of 2 to 7 mm. In addition, the open area ratio (ratio of the area of the through holes to the area of the perforated baffle) is preferably 3 to 15%. If it is less than 3%, the circulation amount decreases and the flow of liquid becomes slow,
This is because if it exceeds 15%, some portions of the liquid flow faster.

As the plating liquid discharge pipe and the air discharge pipe, for example, those in which 7 to 10 pipes are arranged in the plating tank and a large number of discharge holes are arranged on the upper side thereof are used. Also,
An air pump is connected to the air discharge pipe via an air pipe.

It is preferable that the bottom of the plating tank is provided with an inclined bottom surface, and a return pipe, a return pump, and a filter for returning the plating solution to the overflow chamber are connected to the lower portion of the bottom surface. As a result, the accumulation of dust and foreign matter on the bottom of the plating tank is eliminated and the circulation of the plating solution is further improved. Therefore, no foreign matter is mixed in the plating liquid, and the plating liquid is always in a clean state.

[0015]

In the chemical plating tank of the present invention, it has a plating solution discharge pipe, a perforated straightening plate, and an air discharge pipe, which are arranged below the plating bath in order toward the upper side. Therefore, it is possible to smoothly supply the plating liquid from below the plating tank to above.

Further, the flow velocity and dispersion of the plating solution are uniformly controlled by the porous straightening plate. Therefore, the flow velocity and dispersion of the plating solution are uniform, and the plating failure of the object to be processed does not occur. Further, since the air discharge pipe is arranged above the porous straightening plate, the flow velocity and dispersion of the plating solution become more uniform due to the bubbling effect of air. That is, the air jetted from the air discharge pipe rises along the plating liquid rectified by the perforated rectifying plate. Therefore, the plating solution in the bath becomes almost uniform.

Therefore, the dead zone of the plating solution, which has been generated in the conventional plating bath, is not generated. Therefore, plating failure does not occur on the object to be processed. An overflow chamber is arranged outside the plating bath. Therefore, the extra plating solution in the plating tank flows out into the overflow chamber. Therefore, the flow and circulation of the plating solution are improved.

As a result, the distribution of the amount of dissolved oxygen in the plating solution becomes uniform, and plating defects do not occur on the object to be treated. Further, the plating liquid that has flowed into the overflow chamber is filtered by a filter. Therefore, foreign matter such as dust does not remain in the plating solution. Therefore, according to the present invention, it is possible to provide a chemical plating tank in which the flow rate and the dispersion of the plating solution are uniform and the defective plating does not occur on the object to be processed.

[0019]

【Example】

Example 1 A chemical plating bath according to an example of the present invention will be described with reference to FIGS. The chemical plating tank 1 of this example is shown in FIG.
As shown in FIG. 2, a plating tank 11 containing the plating solution 2 and the object to be treated 3 and an overflow chamber 1 provided outside the plating tank 11.
2, a plating solution discharge pipe 13 arranged below the plating bath 11 in order from below to above, a perforated straightening plate 14 and an air discharge pipe 15.

Further, a circulation pipe 131 for circulating the plating solution 2 flowing into the overflow chamber 12 to the plating solution discharge pipe 13, a circulation pump 16 and a filter 17 interposed therein, and an air pipe for the air discharge pipe 15. 15
1 connected to the air pump 19.

The overflow chamber 12 is shown in FIGS.
As shown in FIG. 5, the plating bath 11 is arranged at the entire outer peripheral edge portion. In addition, it is made of polypropylene or Teflon-coated FRP inside the plating tank 11 and the overflow chamber 12.

The overflow chamber 12 is shown in FIG.
As shown in FIG. 5, a circulation pipe 131 for circulating the plating solution discharge pipe 13, a circulation pump 16 and a filter 17 and a heat exchanger 18 provided on the circulation pipe 131 are connected. As shown in FIG. 3, the porous rectifying plate 14 has a large number of plating solution flow holes 140 for making the flow rate and the distribution of the plating solution 2 uniform. This plating liquid flow hole 140 is
It consists of a round hole with a diameter of about 3 mm. The porosity is about 3% with respect to the entire area.

The porous rectifying plate 14 is made of FRP resin molded plate coated with polypropylene or Teflon. This makes it possible to obtain the perforated straightening plate 14 that is lightweight and has excellent durability and chemical resistance. The plating liquid discharge pipe 1
As shown in FIG. 4, 3 is a polypropylene resin molded pipe provided with a large number of plating solution discharge ports 130. The plating solution discharge port 130 is a round hole having a diameter of about 6 mm.

The seven plating solution discharge pipes 13 are arranged in parallel. Each plating solution discharge pipe 13 is connected to a circulation pipe 131, as shown in FIGS. As shown in FIGS. 1 and 2, six air discharge pipes 15 are arranged in parallel above the perforated straightening plate 14 and substantially below the workpiece 3.

Then, as shown in FIG. 2, these air discharge pipes 15 are connected to the air pipes 151, respectively. The air discharge pipe 15 is made of Teflon (poly 4).
Fluorinated ethylene) resin molded pipe. Further, it has a large number of air discharge ports having a diameter of 0.5 mm. As shown in FIGS. 1 and 2, the plating bath 1 and the overflow chamber 12 are made of polypropylene or Teflon-coated FRP rectangular parallelepiped. As a result, the plating solution 2
It has excellent durability and chemical resistance against other chemicals. The plating tank 1 has a volume of about 1000 liters.

Next, the function and effect will be described. As shown in FIG. 1, the chemical plating tank 1 of the present example has a plating solution discharge pipe 13, a perforated straightening plate 14, and an air discharge pipe 15 which are sequentially arranged below the plating tank 11 in an upward direction. Therefore, the plating bath 2 is supplied to the plating tank 11
It can be performed smoothly from below to above.

Further, the flow rate and dispersion of the plating solution 3 are uniformly controlled by the porous straightening plate 14. Therefore, the flow velocity and dispersion of the plating liquid 3 are uniform, and no plating failure occurs on the surface of the object 3 to be processed such as a printed wiring board. Also,
Since the air discharge pipe 15 is disposed above the perforated baffle plate 14, the flow velocity and dispersion of the plating solution 2 become uniform due to the air bubbling effect. That is, the air jetted from the air discharge pipe 15 rises along the plating liquid 2 rectified by the perforated rectifying plate 14. Therefore, the plating solution 2 in the bath is in a substantially uniform state.

As a result, the conventional plating tank 9 (see FIG. 8)
The dead zone 22 of the plating solution 2 which has been caused in the case of 1. Therefore, plating failure does not occur on the object 3 to be processed. An overflow chamber 1 is provided outside the plating tank 11.
2 are provided. Therefore, the extra plating liquid 2 in the plating tank 11 flows out into the overflow chamber 12. Therefore, the flow and circulation of the plating solution 2 are improved.

As a result, the distribution of the dissolved oxygen in the plating solution 2 becomes uniform, and plating defects do not occur on the object 3 to be processed. Further, the plating solution 2 flowing out into the overflow chamber 12 is filtered by the filter 18. Therefore, foreign matter such as dust does not remain in the plating solution 2. Further, since the circulation pipe 131 is provided with the heat exchanger 17, the temperature of the plating solution 2 is kept constant.

Example 2 In this example, as shown in FIG. 5, in the chemical plating tank 1 of Example 1 described above, an inclined bottom surface 103 is further provided, and a second circulation pipe and a return pipe 40 and a return pump as a circulation pump are provided. 41 and 41 are provided.

Return pipe 40 and return pump 41
Has a filter 42 for removing large dust in the plating tank 1, as shown in FIG. Further, as shown in FIG. 5, the bottom of the plating tank 11 has an inclined bottom surface 103 directed downward.

A return pipe 40 and a return pump 41 for returning the plating solution 2 to the overflow chamber 12 are connected to the lower part of the inclined bottom surface 103. This return pump 41 is
It is connected to a plating solution discharge port 104 protruding below the plating tank 11. Others are the same as in the first embodiment.

According to this example, the inclined bottom surface 103 has a role of moving foreign matters such as dust accumulated at the bottom of the plating tank 11 to the plating solution discharge port 104 below. Therefore, in the bottom portion of the plating tank 11, foreign matters such as dust gather in one place of the plating solution discharge port 104 and are easily discharged. Therefore, as compared with the first embodiment, the circulation and cleaning of the plating solution 2 becomes easier. In addition, the same effect as that of the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is a side view of a chemical plating tank according to a first embodiment.

FIG. 2 is a plan view of the chemical plating bath according to the first embodiment.

FIG. 3 is a plan view of a porous straightening vane according to the first embodiment.

FIG. 4 is a plan view of a plating liquid discharge pipe according to the first embodiment.

FIG. 5 is a side view of the chemical plating bath according to the second embodiment.

FIG. 6 is a side view of a conventional chemical plating bath.

FIG. 7 is a plan view of a conventional chemical plating bath.

FIG. 8 is an explanatory view showing a problem of the conventional chemical plating bath.

[Explanation of symbols]

 1. ． ． Chemical plating bath, 11. ． ． Plating bath, 12. ． ． Overflow chamber, 13. ． ． Plating solution discharge pipe, 131. ． ． Circulation pipe, 14. ． ． Porous straightening plate, 15. ． ． Air discharge pipe, 151. ． ． Air pipe, 16. ． ． Circulation pump, 17. ． ． Filter, 19. ． ． Air pump, 2. ． ． Plating solution, 3. ． ． Object to be processed,

Claims (2)

[Claims] 1. A plating tank for containing a plating solution and an object to be treated, an overflow chamber provided outside the plating tank, a plating solution discharge pipe arranged below the plating tank in order from below to above, and perforated rectification. A plate and an air discharge pipe, a circulation pipe for circulating the plating liquid flowing out into the overflow chamber to the plating liquid discharge pipe, a circulation pump and a filter provided in the circulation pipe, and an air pipe connected to the air discharge pipe. A chemical plating bath, which is composed of a connected air pump. 2. The bottom of the plating tank according to claim 1,
A chemical plating having an inclined bottom surface facing downward, and a return pipe for returning the plating solution to the overflow chamber is connected to a lower portion of the inclined bottom surface, and a return pump and a filter are provided in the return pipe. Tank.