JPH05339794A - Method for circulating plating solution in electroplating - Google Patents

Abstract

PURPOSE:To improve the cleanliness and uniformity of a plating soln. at the time of returning the plating soln. to a plating soln. circulating tank from a group of plating tanks by returning the plating soln. returned from some plating tanks to another plating soln. circulating tank. CONSTITUTION:A plating soln. is supplied from plating soln. circulating tanks 2A, 2B and 2C to the corresponding groups 1A, 1B and 1C of plating tanks. The plating soln. is returned from the first tanks 1B1 and 1C1 to the adjacent tanks 2A and 2B. The plating soln. is increased in amt. in the tank 2A and decreased in the tank 2C. The unbalance is eliminated by supplying the plating soln. to an additional equipment 7 from the tank 2A and then supplying the flow-controlled plating soln. to the tank 2C. Since the entire plating soln. passes through the equipment 7, the uniformity in composition and cleanliness of the plating soln. are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks.

[0002]

2. Description of the Related Art A conventional method for circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks will be described below with reference to the drawings. FIG. 10 shows an example of a conventional plating solution circulation system in the case of using a plating tank 1 composed of three plating solution circulation tanks 2A, 2B, 2C and 14 plating tanks. In this circulation system, the plating tank 1 corresponds to each of the plating solution circulation tanks 2A, 2B, and 2C, and three groups (1
A, 1B, 1C). In the present specification, all plating lines are assumed to proceed from left to right in the figure. That is, in the plating tank, the 1A side is upstream and the 1C side is downstream.

In this section, when the plating solution is supplied, the plating solution is supplied from the respective plating solution circulation tanks 2A, 2B, 2C to the corresponding plating tank groups 1A, 1B, 1C, and from the plating tanks 1A, 1B, 1C. The discharged plating solutions are returned to the plating solution circulation tanks 2A, 2B and 2C, respectively. This was done in order to keep the amount of liquid in each plating solution circulation tank constant. On the other hand, a predetermined amount of plating components consumed in the plating process in the plating tank 1 is replenished by the auxiliary equipment 7, and the auxiliary equipment 7 also includes a filter equipment for removing foreign matters in the plating solution.

In FIG. 10, 3A, 3B and 3C are plating liquid supply pipes, 4A, 4B and 4C are plating liquid drain pipes, 5a, 5b and 5c are pumps, 6 is a strip,
Reference numerals 8a and 8b are communication pipes, and 9a and 9b are auxiliary equipment circulation pipes. However, in the circulation method shown in FIG. 10, only the plating solution in the plating solution circulation tank 2C is replenished and filtered, and the concentration of the entire plating solution cannot be controlled. Therefore, an improved version of the circulation method shown in FIG. 10 is shown in FIGS.

That is, in the circulation method shown in FIG. 11, the plating solution taken out from the plating solution circulation tank 2B is subjected to component adjustment and filtering, and then returned to the plating solution circulation tank 2C. At this time, since the liquid level difference constantly occurs between the plating solution circulation tank 2B and the plating solution circulation tank 2C, the plating solution flows through the communication pipe 8b. As a result, the plating solutions in the plating solution circulating tanks 2B and 2C are mixed, and the uniformity of the plating component concentration is increased. However, since the plating solution circulation tank 2A is out of the system of this convection, it is mixed only by convection due to diffusion or uncertain liquid surface level difference, and it is not possible to expect uniform concentration of plating components.

In the circulation method shown in FIG. 12, which is a further improvement of the circulation method shown in FIG. 11, all the plating solution circulation tanks are attached to the auxiliary equipment 7.
Since it is included in the system for circulating the plating solution, the uniformity of the plating component concentration of the plating solution is improved. However, in the present circulation method, since the liquid transfer from the plating solution circulation tanks 2C to 2B and from the plating solution circulation tanks 2B to 2A depends on the liquid level of the plating solution circulation tank, the plating solution circulation tank with the lowest liquid level is In 2A, there was a problem that the operation of the plating solution circulation pump 5a became unstable due to the reduction of the suction head. As measures against this, increase in suction head of the plating solution circulation pump 5a due to enlargement of the plating solution circulation tank, reduction in liquid level difference between the plating solution circulation tanks due to increase in diameter of the communication pipes 8a and 8b, and additional equipment 7 By reducing the circulating amount of the plating solution, the level difference between the plating solution circulating tanks has been reduced. However, as a result of this measure, the plating solution circulation tank becomes larger and the cost increases due to an increase in the plating solution amount, the limit of the liquid level difference between the plating solution circulation tanks due to the limit of the diameter of the communicating pipe 8 increases, and the equipment cost increases. As a result, problems such as a decrease in plating component replenishment ability and a decrease in plating solution filtering ability due to a decrease in the circulating fluid amount of incidental equipment occurred.

The circulation method shown in FIG. 13 is obtained by further modifying the circulation method shown in FIG. This circulation method is characterized in that the plating solution taken out from the plating solution circulation tank 2B is subjected to plating component adjustment, filtering, etc. in the auxiliary equipment 7, and then uniformly returned to each plating solution circulation tank 2A, 2B, 2C. The drawbacks of the various circulation methods described above have been largely compensated. However, since the configuration of the incidental equipment and its control are complicated, the reliability of the equipment is lowered and the equipment cost is inevitable.

The circulation method shown in FIG. 14 uses one plating solution circulation tank 2 and is very suitable for a small-scale plating facility (Japanese Patent Publication No. 57-10198).
(See the official gazette). However, the total capacity of recent plating equipment size is significantly plating solution circulating tank has a 200 meters ³ or more, very uneconomically is placing the plating solution circulating tank such large in plating yard And
Further, there is a problem that the plating solution concentration cannot be expected to be uniform in such a large tank.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for circulating a plating solution in electroplating which solves the above problems.

[0010]

A first aspect of the present invention is a method of circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks, wherein the number of electroplating tanks is equal to the number of plating solution circulation tanks. The plating solution circulation tank is divided into groups and the adjacent plating solution circulation tank is connected to the adjacent plating solution circulation tank by communication piping, and the plating solution is supplied from each plating solution circulation tank to the corresponding plating tank group, and plating is performed from the plating tank group. When returning the solution to the plating solution circulating tank, the returning plating solution from one plating tank or a plurality of plating tanks was returned to another plating solution circulating tank, and as a result, was excessively returned to another plating solution circulating tank. A method of circulating a plating solution in electroplating, which comprises returning an amount of the plating solution corresponding to the plating solution to the original plating solution circulation tank having a small return amount.

A second aspect of the present invention is a method of circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks, wherein the electroplating tank is divided into a number of plating tank groups equal to the number of plating solution circulation tanks. In addition, the plating solution circulation tank is connected to the adjacent plating solution circulation tank by a communication pipe, the plating solution is supplied from each plating solution circulation tank to the corresponding plating tank group, and the plating solution is circulated from the plating tank group. When returning to the tank, the plating solution returned from the plating tanks at both ends is directly sent to auxiliary equipment for treatment and then returned to the plating solution circulation tank, which is a method for circulating the plating solution in electroplating.

A third invention is a method of circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks, wherein the electroplating tank is divided into a group of plating tanks equal in number to the plating solution circulation tanks, In addition, the plating solution circulation tank is connected to the adjacent plating solution circulation tank by a communication pipe, the plating solution is supplied from each plating solution circulation tank to the corresponding plating tank group, and the plating solution is circulated from the plating tank group. When returning to the tank, the plating solution returned from one plating tank or a plurality of plating tanks is returned to another plating solution circulation tank, and as a result, it corresponds to the plating solution excessively returned to another plating solution circulation tank. When returning a large amount of plating solution to the original plating solution circulation tank with a small amount of return, the return plating solution from the plating tanks at both ends is sent directly to auxiliary equipment for processing A circulating process of the plating solution in electroplating and returning to the gas-liquid circulation tank.

Further, the plating solution returned to the other plating solution circulation tank in the first and third inventions is returned to the adjacent plating solution circulation tank, and the plating tank group supplied from the adjacent tank to another plating solution circulation tank. The plating solution to be returned to the tank is further returned to the plating solution circulation tank adjacent to the adjacent tank, and the plating solution is caused to flow in one direction in a cascade manner.

[0014]

In the first aspect of the invention, when the plating solution is returned from the plating tank group to the plating solution circulating tank, the whole amount of the plating solution is not returned to the plating solution circulating tank but from one plating tank or a plurality of plating tanks. Return the plating solution returned to the other plating solution circulation tank, and as a result, return the plating solution equivalent to the plating solution excessively returned to the other plating solution circulation tank to the original plating solution circulation tank with a small amount of return. As a result, the plating components can be adjusted and filtered with respect to the total amount of the plating solution, the plating quality can be improved by improving the cleanliness and uniformity of the plating solution, and the pressing scratch trouble due to the reduction of foreign matter in the plating solution can be achieved.

The second aspect of the present invention is to send the plating solution in both ends of the plating tank containing foreign matter such as dust or excess water directly to the auxiliary equipment for processing and then returning it to the plating solution circulation tank. Therefore, it is possible to further improve the cleanliness of the plating solution, the improvement of the plating quality by improving the uniformity, and the reduction of the pressing scratch trouble due to the reduction of foreign matters in the plating solution.
Moreover, since only the plating solution containing excess water can be supplied to the evaporator of the auxiliary equipment, the auxiliary equipment can be downsized, the running cost can be reduced, and the operating condition can be stabilized.

The third invention is a combination of the first and second inventions. In the first and third inventions, plating to be returned to another plating solution circulation tank is returned to an adjacent plating solution circulation tank, and is to be returned from the plating tank group supplied from the adjacent tank to another plating solution circulation tank. Further effects can be achieved by returning the solution to the plating solution circulating tank adjacent to the adjacent tank and sequentially flowing the plating solution in the same direction, that is, in a cascade manner.

[0017]

【Example】

Embodiment 1 An embodiment of the first invention will be described with reference to FIGS.
FIG. 1 shows an embodiment of the first invention and shows a plating solution circulating system using three plating solution circulating tanks 2A, 2B, 2C and 14 plating tanks 1. In this circulation system, the plating tank 1 includes each plating solution circulation tank 2A, 2A.
It is divided into three groups (1A, 1B, 1C) corresponding to B and 2C.

In this section, when the plating solution is supplied, the plating solution is supplied from the respective plating solution circulation tanks 2A, 2B, 2C to the corresponding plating tank groups 1A, 1B, 1C. 1C to plating solution circulation tank 2
When the plating solution returns to A, 2B, and 2C, the returning plating solution from the first tank of the plating tank group is returned to the adjacent plating solution circulation tank, not to the original plating solution circulation tank.

That is, of the plating solutions supplied from the plating solution circulation tank 2C to the plating tank group 1C through the plating solution supply pipe 3C and the plating solution circulation pump 5a, the plating solution returned from the plating tank 1C ₁ is the plating solution. Drainage pipe 4
Return to the adjacent plating solution circulation tank 2B through E,
The plating solution returned from the remaining tank is the plating solution circulation tank 2
It returns to C. Further, from the plating solution circulation tank 2B to the plating solution supply pipe 3B and the plating solution circulation pump 5a.
Of the plating solution supplied to the plating tank group 1B through
The returning plating solution from the plating tank 1B ₁ is returned to the adjacent plating solution circulating tank 2A through the plating solution drain pipe 4D, and the returning plating solution from the remaining tanks is returned to the plating solution circulating tank 2B. Further, all the plating solution supplied from the plating solution circulation tank 2A to the plating tank group 1A through the plating solution supply pipe 3A and the plating solution circulation pump 5a is returned to the plating solution circulation tank 2A.

As a result of these operations, in the plating solution circulating tank 2A, the plating solution corresponding to the amount of circulating solution for one plating tank increases, and for the plating solution circulating tank 2C, the amount of circulating solution for one plating tank. The plating solution corresponding to is reduced. In order to absorb this imbalance in the plating solution amount, a plating solution equivalent to the circulating solution amount for one plating tank is sent from the plating solution circulation tank 2A to the auxiliary equipment 7, and the plating solution adjusted by the auxiliary equipment is further supplied. Is sent to the plating solution circulating tank 2C.

By the above operation, a part of the plating solution is partially contained in the plating solution circulating tank 2C, the plating tank group 1C, the plating solution circulating tank 2B, the plating tank group 1B, and the plating solution circulating tank 2A.
The auxiliary equipment 7 circulates in the route of the plating solution circulation tank 2C. Therefore, the entire plating solution passes through the auxiliary equipment 7 almost uniformly, and the uniformity and cleanliness of the components of the plating solution are improved. In addition, in this circulation system, the plating solution circulation pump 5a
There is no problem if all the discharge amounts of the plating liquids are equal, but the discharge amount is usually non-uniform, and in order to absorb the imbalance of the plating liquid amount between the plating liquid circulation tanks due to the difference in the discharge amount, the communication pipes 8a and 8b are It is provided.

There is no problem if the plating solution is circulated in the direction opposite to that of the present circulation system, but it is inevitable that the profit that can be enjoyed will be reduced. As described above, in the figure, the strip 6 enters the plating tank from the left side and goes out to the right side. However, since foreign matter in the plating solution is mainly brought in from the pretreatment step such as pickling, While the plating solution in the side plating solution circulation tank 2A is most contaminated, the plating solution for performing the plating of the uppermost layer is clean and uniform, so that a good plating appearance can be obtained. It is most preferable to supply the solution to the final plating tank group on the right end and to use it by tracing back to the upstream side in order to guide the return liquid from the most contaminated left end tank group directly to the incidental equipment. There is no end.

The circulation system shown in FIG. 2 shows a case where two plating solution circulation tanks 2A and 2B are used, and functions similarly to the circulation system shown in FIG. For alloy plating, which requires evenness and cleanliness of the plating solution, as shown in FIG.
It can correspond to circulate the plating solution corresponds to 1B _1, 1B ₂ and 1C _1, 1C circulation of _half of the 1C group group.

As a result of carrying out the method of the present invention of FIG. 1 in an actual operation, the concentration of the plating solution component is a target value ± of the conventional method.
The target value of 10g / l was improved to ± 2g / l. In addition, the difference in the liquid level between the plating solution circulation tanks is conventionally ± 0.5 to
Although it was 1.0 m, it was improved to 150 mm or less, which reduced the amount of plating solution by 14 to 34 m ^{3 when} the bottom area of the circulation tank was 20 m ² .

Embodiment 2 Next, an embodiment of the second invention will be described with reference to FIGS. FIG. 4 shows an embodiment of the second invention, and the configurations of the plating solution circulating tank and the plating tank are the same as those of FIG. 1 which is the embodiment of the first invention. The plating solution supply system is also the same, but when the plating solution returns from the plating tank groups 1A, 1B, 1C to the plating solution circulation tanks 2A, 2B, 2C, one tank at each end of the plating tank 1, that is, a group 1A. 1A ₁ and 1
Regarding the return from 1C _{4 of the} group C, it is not returned to the plating solution circulation tank, but is temporarily returned to the incidental equipment 7, and foreign matter is removed by filtering, water is removed by an evaporator, and plating solution components are replenished before circulating the plating solution. Tank 2
It was configured to return to C.

The first tank 1A ₁ of the plating tank has the largest amount of foreign matter such as dust and water brought in from the pretreatment step such as pickling (not shown), and the final tank for plating, 1C in FIG.
_{In No. 4} , washing with water is usually performed, and the amount of this washing water mixed in the plating solution is the largest. Therefore, for each of the tanks at both ends, that is, for 1A ₁ , the auxiliary equipment circulation pipes 9a and 1C ₄ are returned to the auxiliary equipment 7 by the auxiliary equipment circulation pipes 9a ', and the other plating liquids are directly circulated in the corresponding plating solution Put it back in the tank.

As a result of the above construction, the plating solution circulating tank 2
As for C, the liquid volume increases by one plating tank, and the communication pipe 8b,
The plating solution flows out to the plating solution circulation tanks 2B and 2A via 8a. Therefore, the plating solution circulates in the path of the plating solution circulation tank 2A, the plating tank group 1A, the auxiliary equipment 7, the plating solution circulation tank 2C, the plating solution circulation tank 2B, the plating solution circulation tank 2A, and the entire plating solution is almost evenly distributed. By passing through the auxiliary equipment, it is possible to selectively treat the plating solution at both ends where foreign matters such as dust and excessive water are mixed, so that the uniformity and cleanliness of the plating solution components are improved. .. The communication pipes 8a and 8b absorb the imbalance of the liquid amount in the plating liquid circulation tank due to the difference in the pump discharge amount, as in the first embodiment. Since the type and amount of processing in the auxiliary equipment 7 are almost specified, the device specifications inside the auxiliary equipment 7 can be appropriately determined.

Although it is possible to return the return liquid from the auxiliary equipment 7 to the plating solution circulation tank 2A or 2B, the most downstream plating solution circulation tank 2C used when plating the uppermost layer is used. As described above, it is preferable to be clean and uniform. Figure 2 shows 2
This is a case where the base plating solution circulation tank is used, and functions similarly to the circulation system shown in FIG.

In the case of alloy plating, which requires evenness and cleanliness of the plating solution, as shown in FIG. 6, the return liquid from the auxiliary equipment 7 is supplied by the auxiliary equipment circulation pipes 9b, 9b ', 9 ". The plating solution circulating tanks 2A, 2B, and 2C can be equally divided and returned.Comparing the structure of this embodiment, for example, FIG. To pump 5 in Figure 12
b and 5c are not required, and it is possible to supply only the part where excess water is mixed to the evaporator, and the evaporator can be downsized. Steam consumption is 20%, cooling water consumption is 25%. In addition, since only the plating solution with low cleanliness is filtered, the filter is downsized and running cost is reduced, and at the same time, the operating condition is stable, the concentration of plating components is fluctuated, and the incidental equipment is downsized. As a result, the same effect as in Example 1 was recognized even when the amount of the plating solution circulating through the auxiliary equipment was decreased and the fluctuation of the liquid level between the plating solution circulation tanks was decreased.

Embodiment 3 Next, an embodiment of the third invention will be described with reference to FIGS. FIG. 7 shows an embodiment of the third invention and is different from FIG. 1 which is the embodiment of the first invention in that, as in the case of the second embodiment, the entrance side end portion in which foreign matter such as dust is mixed. The plating solution in the plating tank 1A ₁ is directly sent to the auxiliary equipment 7 to remove foreign matters, and then returned to the plating solution circulation tank 2C, and plating of the plating tank 1C _{4 at} the end of the outlet side where excessive water is mixed. Similarly, the solution was sent directly to the auxiliary equipment 7 to remove excess water and then returned to the plating solution circulation tank 2C.
The same as the embodiment of

The circulation system shown in FIG. 8 shows a case where two plating solution circulation tanks 2A and 2B are used, and functions similarly to the circulation system shown in FIG. further,
As shown in FIG. 9, a plating tank 2 layer 1 is used for alloy plating etc. which requires more uniform plating solution and cleanliness.
It is possible to respond by circulating a plating solution corresponding to the circulation amount of B ₁ , 1B ₂ , and 1C ₁ , 1C ₂ .

As a result of carrying out the method of the present invention of FIG. 4 in an actual operation, a more excellent effect was obtained as compared with the case of FIG. 1 described above. In addition, the amount of steam used in the evaporator was conventionally 4 t / hr, but in the case of the present invention, it is 3.3 t / hr.
The amount of cooling water used was conventionally 230 t / hr, but in the case of the present invention it was reduced to 170 t / hr.

[0033]

The effects obtained by the present invention are as follows. Since the total amount of the plating solution can be adjusted and filtered, the plating quality can be improved by improving the cleanliness and uniformity of the plating solution, and the number of foreign matter in the plating solution can be reduced to reduce the scratching trouble.

Since the liquid level difference between the plating solution circulating tanks can be reduced, it is possible to reduce the amount of the plating solution and downsize the plating solution circulating tank. Since the difference in the liquid level between the plating solution circulation tanks and the fluctuation of the liquid level are reduced, the operation of the plating solution circulation pump is stable, and the problems of the circulation pump and the piping system are reduced (improved operational stability). It is possible to stabilize the plating quality.

Furthermore, if a plating tank is provided above the plating solution circulation tank, the return of the plating solution from the plating tank can be performed by gravity, and the equipment can be installed without providing a pump dedicated to the circulation of incidental equipment, resulting in equipment cost. It is possible to prevent an increase in running cost (electric power cost). Further, in the second and third inventions, in addition to the above,
Since only the plating solution mixed with excess water can be supplied to the evaporator, the evaporator can be downsized, the running cost can be reduced, and the operating condition can be stabilized.

[Brief description of drawings]

FIG. 1 is a diagram of a plating solution circulation system according to an embodiment of the first invention.

FIG. 2 is a diagram showing a plating solution circulation system according to another embodiment of the first invention.

FIG. 3 is a plating solution circulation system diagram of another embodiment of the first invention.

FIG. 4 is a diagram showing a plating solution circulation system according to an embodiment of the second invention.

FIG. 5 is a diagram showing a plating solution circulation system according to another embodiment of the second invention.

FIG. 6 is a diagram showing a plating solution circulation system according to another embodiment of the second invention.

FIG. 7 is a diagram of a plating solution circulation system according to an embodiment of the third invention.

FIG. 8 is a diagram showing a plating solution circulation system according to another embodiment of the third invention.

FIG. 9 is a diagram showing a plating solution circulation system according to another embodiment of the third invention.

FIG. 10 is a diagram of a conventional plating solution circulation system.

FIG. 11 is a diagram of a conventional plating solution circulation system.

FIG. 12 is a diagram of a conventional plating solution circulation system.

FIG. 13 is a diagram of a conventional plating solution circulation system.

FIG. 14 is a diagram of a conventional plating solution circulation system.

[Explanation of symbols]

1 plating tank 1A plating tank group 1A ₁ plating tank 1A ₂ plating tank 1B plating tank group 1B ₁ plating tank 1B ₂ plating tank 1B ₇ plating tank 1C plating tank group 1C ₁ plating tank 1C ₂ plating tank 1C ₄ plating tank 2A plating solution Circulation tank 2B Plating liquid circulation tank 2C Plating liquid circulation tank 3A Plating liquid supply pipe 3B Plating liquid supply pipe 3C Plating liquid supply pipe 4A Plating liquid drainage pipe 4B Plating liquid drainage pipe 4C Plating liquid drainage pipe 4D Plating Liquid drainage pipe 4E Plating liquid drainage pipe 5a Pump 5b Pump 5c Pump 6 Strip 7 Ancillary equipment 8a Communication pipe 8b Communication pipe 9a Ancillary equipment circulation pipe 9a 'Ancillary equipment circulation pipe 9b Ancillary equipment circulation pipe 9b' Ancillary equipment circulation pipe 9b ”Ancillary equipment circulation piping

Claims (4)

[Claims] 1. A method of circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks, wherein the electroplating tank is divided into a group of plating tanks equal in number to the plating solution circulation tanks, and the plating solution circulation is performed. When connecting the tank to the adjacent plating solution circulation tank with communication piping, supplying the plating solution from each plating solution circulation tank to the corresponding plating tank group, and returning the plating solution from the plating tank group to the plating solution circulation tank , The plating solution returned from one plating tank or multiple plating tanks is returned to another plating solution circulation tank, and as a result, an amount of plating solution equivalent to the plating solution excessively returned to another plating solution circulation tank is supplied. A method for circulating a plating solution in electroplating, which is characterized by returning to the original plating solution circulation tank with a small amount of return. 2. A method of circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks, wherein the electroplating tank is divided into a group of plating tanks equal in number to the plating solution circulation tanks, and the plating solution circulation is performed. When connecting the tank to the adjacent plating solution circulation tank with communication piping, supplying the plating solution from each plating solution circulation tank to the corresponding plating tank group, and returning the plating solution from the plating tank group to the plating solution circulation tank A method for circulating a plating solution in electroplating, wherein the plating solution returned from the plating tanks at both ends is directly sent to auxiliary equipment for treatment and then returned to the plating solution circulation tank. 3. A method of circulating a plating solution in an electroplating facility having a plurality of plating solution circulation tanks, wherein the electroplating tank is divided into a group of plating tanks equal in number to the plating solution circulation tanks, and the plating solution circulation is performed. When connecting the tank to the adjacent plating solution circulation tank with communication piping, supplying the plating solution from each plating solution circulation tank to the corresponding plating tank group, and returning the plating solution from the plating tank group to the plating solution circulation tank , The plating solution returned from one plating tank or multiple plating tanks is returned to another plating solution circulation tank, and as a result, an amount of plating solution equivalent to the excess plating solution is returned to another plating solution circulation tank. When returning to the original plating solution circulating tank with a small amount of return, the returning plating solution from the plating tanks at both ends is sent directly to incidental equipment for processing, and is also returned to the plating solution circulating tank. A method for circulating a plating solution in electroplating, which comprises: 4. The plating solution returned to another plating solution circulation tank according to claim 1 or 3, is returned to an adjacent plating solution circulation tank, and the plating tank group supplied from the adjacent tank to another plating solution circulation tank. The plating solution to be returned is further returned to the plating solution circulation tank adjacent to the adjacent tank,
The method for circulating a plating solution in electroplating according to claim 1 or 3, wherein the plating solution is cascaded in one direction.