JP3178164B2 - Electroplating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic plating apparatus for plating a surface of an object to be plated such as a lead frame with silver or solder.

[0002]

2. Description of the Related Art In order to apply a surface treatment such as silver or solder to an object to be plated such as a lead frame, plating is generally performed by an electrolytic plating apparatus. Electroplating equipment
An object to be plated is placed in conduction with the cathode in a state opposite to the anode placed in the plating solution in the plating bath, and the metal is applied to the surface of the object using the reduction of metal cations in the plating solution. It is to be deposited.

In order to perform a high-speed plating process using such an electrolytic plating apparatus, a stirring mechanism for strongly stirring the plating solution using the pressure of air is provided, or the plating solution is immersed in the plating solution. A rocking mechanism for rocking the object to be plated is provided, and both are stirred and rocked by arranging them side by side. An important requirement along with the speeding up of the plating process is to make the plating thickness uniform. In order to obtain a uniform plating thickness, a shielding plate is provided between the anode and the object to be plated, or an auxiliary cathode is provided near the so-called high current density part such as a corner of the object to be plated. To reduce current concentration on

[0004]

However, in such an electroplating apparatus, in order to perform a high-speed and uniform plating process, a swing mechanism and a stirring mechanism, a shielding plate and an auxiliary cathode are provided, respectively. Opposing effects occur. In other words, even if an attempt is made to vigorously stir the plating solution using a stirring mechanism in order to perform high-speed plating, sufficient stirring is hindered by the shielding plate provided between the anode and the object to be plated. Further, when the object to be plated is swung by the swing mechanism, the swinging motion is limited by the auxiliary cathode. As described above, when plating is performed, it is very difficult to simultaneously increase the speed and uniformity of the processing.

[0005]

SUMMARY OF THE INVENTION The present invention is an electrolytic plating apparatus made to solve such a problem. That is, in this electrolytic plating apparatus, an object to be plated, which is electrically connected to a cathode, is disposed in the vicinity of an anode disposed in a plating solution in a plating tank, and a metal is deposited on the surface of the object to be plated. A swing mechanism for swinging the object to be plated in the solution is provided, and a blowing means is provided to send out the plating solution in the direction of the object to be plated. Further, a suction means is provided for drawing in the plating solution sent from the blowing means and hitting the object to be plated.

Further, a blowing means is disposed on the opposite side of the object to be plated with respect to the anode, and the plating solution is sent out toward the object to be plated through the anode. A blowing means and a suction means are arranged on the side opposite to the object to be plated with respect to the anode. Further, a suction means is disposed on the opposite side of the object to be plated with respect to the anode, and a blowing means is provided adjacent to the anode, and a plating solution containing a metal cation is drawn in from the suction means, and the plating solution is plated from the blowing means. It is also an electroplating device that sends it out to a product.

[0007]

[Function] Since the object to be plated is opposed to the anode disposed in the plating solution, the concentration of metal cations on so-called high current density portions such as corners of the object to be plated is eliminated, and uniform plating is achieved. Thickness is obtained. Also, by sending the plating solution from the blowing means toward the object to be plated, and drawing in the plating solution that has hit the object to be plated by the suction means, without causing the plating solution between the anode and the object to be plated to stay, High-concentration metal cations can always be sent to the vicinity of the object to be plated, and high-speed plating can be performed.

That is, by disposing the blowing means on the opposite side of the object to be plated with respect to the anode, the plating solution is sent out over the anode, and a high concentration of metal cations can be supplied to the object to be plated. On the contrary, by disposing the suction means on the opposite side of the object to be plated with respect to the anode, once the high concentration metal cations are drawn in, the blowing means collectively moves from the blowing means to the object to be plated. A high concentration of metal cations can be supplied even if it is sent out, so that high-speed plating can be performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electrolytic plating apparatus according to the present invention will be described below with reference to the drawings. In the drawings used in the following description, the plating solution is not particularly shown, but is assumed to be filled in the plating tank. FIG. 1 is a perspective view illustrating the electrolytic plating apparatus of the present invention. That is, the electrolytic plating apparatus 1 includes an anode 3 in a predetermined plating solution in a plating tank 2.
Is provided, and an object to be plated 10 made of a lead frame or the like which is electrically connected to the cathode is disposed in the vicinity of the anode 3 so as to face each other.
The metal is deposited on the surface of the plating object 10.

The object to be plated 10 is held by a fixing jig 11 attached to a transport bar 12. For example, in the case of a long plating object 10 such as a lead frame, a clip-shaped fixing jig 11 that can hold one side of the long side portion is suitable, and is uniformly applied to the entire plating object 10. A large current.
By holding the object to be plated 10 by such a fixing jig 11 and arranging the object to be plated 10 in the vicinity of the anode 3, the metal cations can be moved linearly,
Concentration of metal cations on the high current density portion can be prevented.

Further, the electroplating apparatus 1 is provided with a swing mechanism 4 composed of, for example, an eccentric cam and a motor.
Plated object 1 via transfer bar 12 and fixing jig 11
0 can be swung in the plating solution. Further, in the plating tank 2, a blowing unit 5 for sending the plating solution toward the plating object 10, and a blowing unit 5.
And a suction means 6 for drawing in a plating solution which has been sent out of the apparatus and which has hit the object to be plated 10 and which has been involved in the plating process.

The blowing means 5 is connected to a first preliminary chamber 7 provided outside the plating tank 2 and has a first pipe 7.
It is connected to a pump (not shown) via a. Also,
The suction means 6 communicates with a second preparatory chamber 8 provided outside the plating tank 2, and is connected to the above-mentioned pump via a second pipe 8a. That is, the operation of this pump causes the plating solution to flow through the first pipe 7a to the first preliminary chamber 7
And is sent out from the blowing means 5 toward the plating object 10. Further, the plating solution involved in the plating process is drawn from the suction means 6 and enters the second preliminary chamber,
Return to the pump via the second pipe 8a. Thus, the plating solution is circulated in the plating tank 2 by the operation of the pump.

Next, the essential parts of the electrolytic plating apparatus 1 of the present invention will be described with reference to the perspective view of FIG. That is, the anode 3
The plurality of plating tanks 2 are arranged on the opposite inner side surfaces of the plating tank 2 in a state of being suspended, respectively, and are provided at predetermined intervals. An object to be plated 10 made of a lead frame or the like as shown in FIG.
When the object to be plated 10 is arranged, the distance between the object to be plated 10 and one of the anodes 3 is set to, for example, 20 mm or less so that the wraparound of metal cations from the anode 3 can be suppressed. Also, behind each anode 3,
Blowing means 5 communicating with the first preliminary chamber 7 is provided, respectively, and supplies the plating solution into the plating tank 2. Further, suction means 6 communicating with the second preliminary chamber 8 is provided between the anodes 3 so as to draw in a plating solution involved in the plating process.

In order to perform a plating process using such an electrolytic plating apparatus 1, first, while holding an object 10 such as a lead frame using a fixing jig 11, the transport bar 12 is swung. Attach to mechanism 4. Then, a predetermined current is caused to flow between the anode 3 and the object to be plated 10 which is a cathode while the object to be plated 10 is oscillated (substantially circular movement) by operating the swing mechanism 4. At the same time, the plating solution is sent out from the blowing means 5 and the plating solution involved in the plating process is drawn in from the suction means 6.

The flow of the plating solution during such a plating process will be described with reference to the schematic diagram of FIG. That is,
The plating solution sent out from the blowing means 5 disposed behind each anode 3 (on the opposite side of the workpiece 10 with respect to the anode 3) flows through the anode 3 as shown by an arrow a in the drawing to be plated. Hit object 10. The plating solution contains a high concentration of metal cations when flowing through the anode 3, and this comes into contact with the surface of the workpiece 10. After the plating process is performed on the surface of the object to be plated 10, the plating solution involved in the plating process is drawn in from the suction means 6 as shown by an arrow b in the figure. Note that the tip of the suction means 6 is provided at a position slightly closer to the plating object 10 than the anode 3, so that the plating solution before participating in the plating process is not drawn.

Due to the flow of the plating solution, the anode 3
Since a plating solution containing a high concentration of metal cations can always be applied to the object to be plated 10 without the plating solution remaining between the object and the object to be plated 10, high-speed plating can be performed. Further, by setting the distance between the anode 3 and the object to be plated 10 close to, for example, 20 mm or less as described above, the wraparound of metal cations can be suppressed, and a uniform plating thickness can be obtained.

As a specific plating process by the electrolytic plating apparatus 1, a plating object 10 composed of a lead frame is used.
Here, an example in which solder plating is performed is shown. The size of the lead frame as the object to be plated 10 is about 200 mm × 32 mm
The distance between the lead frame and the anode 3 was set to 20 mm or less. In the plating solution, the Sn ²⁺ concentration was 27 g / l, the Pb ²⁺ concentration was 3 g / l, and the free acid concentration was 1 g / l.
A composition having a composition of 80 ml / l and a concentration of other additives of 40 ml / l was used. The temperature of the plating solution was set to 30 ° C., and a current density of 40 A / dm ² was passed for 24 seconds. As a result, the surface of the lead frame could be plated with a solder having a thickness of 7 to 9 μm. Was also good.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a perspective view showing a main part of another electrolytic plating apparatus 1. That is, the electroplating apparatus 1 is provided with a mesh electrode 31 as the anode 3, and the blowing means 5 and the suction means 6 are arranged behind the mesh electrode 31. FIG. 5 is a schematic diagram illustrating the flow of a plating solution when the mesh electrode 31 is used. By using the reticulated electrode 31, the plating solution sent from the blowing means 5 passes through the mesh and hits the object 10 to be plated. Pulled in. That is,
By providing the blowing means 5 and the suction means 6 as necessary, the most efficient circulation of the plating solution can be obtained, and the plating process can be speeded up.

FIG. 6 is a schematic diagram for explaining the flow of the plating solution in an example other than the above. That is, in the electroplating apparatus 1, the suction means 6 is disposed behind each anode 3, and the blowing means 5 is provided between each anode 3. In the electroplating apparatus 1, high concentration metal cations present near the anode 3 are once drawn by the suction means 6 (arrow b in the drawing) and accumulated in a reserve tank (not shown) or the like. A plating solution containing ions is sent from the blowing means 5 toward the plating object 10 (arrow a in the figure). By such a flow of the plating solution, the plating solution having a high concentration of metal cations can be constantly applied to the object to be plated 10, and the speed of the plating process can be increased.

In this embodiment, the object to be plated 1
Although a case where a lead frame is mainly used as 0 has been described, the present invention is not limited to this. Also,
Although an example in which a plurality of anodes 3, blowing means 5, and suction means 6 are provided has been described, each may be set according to the size of the workpiece 10.

[0021]

As described above, the electrolytic plating apparatus of the present invention has the following effects. That is, by arranging the object to be plated in the vicinity of the anode, the concentration of metal cations in the vicinity of the high current density portion can be suppressed, so that a uniform plating thickness can be obtained. Furthermore, while the object to be plated swings, the plating solution is sent out from the blowing means toward the object to be plated, and the plating solution involved in the plating process is drawn in by the suction means. Since metal cations can be supplied to the object to be plated, high-speed plating can be performed. From these facts, it is possible to achieve both uniform plating thickness and high-speed plating.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an electrolytic plating apparatus according to the present invention.

FIG. 2 is a perspective view of a main part of the electrolytic plating apparatus of the present invention.

FIG. 3 is a schematic diagram (part 1) illustrating a flow of a plating solution.

FIG. 4 is a perspective view of a main part of another electrolytic plating apparatus.

FIG. 5 is a schematic diagram (part 2) illustrating the flow of a plating solution.

FIG. 6 is a schematic diagram (part 3) illustrating the flow of a plating solution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electroplating apparatus 2 Plating tank 3 Anode 4 Swinging mechanism 5 Blowing means 6 Suction means 7 First preliminary chamber 8 Second preliminary chamber 10 Plated object 11 Fixing jig 12 Transport bar

Claims (4)

(57) [Claims] Claims: 1. An object to be plated, which is electrically connected to a cathode, is disposed in the vicinity of an anode disposed in a plating solution in a plating tank, and is opposed to the anode.
An electroplating apparatus for depositing a metal on a surface of the object to be plated, comprising: a swing mechanism for swinging the object to be plated in the plating solution; and sending the plating solution toward the object to be plated. And a suction means for drawing in a plating solution sent from the blowing means and hitting the object to be plated. 2. The method according to claim 1, wherein the blowing unit is disposed on the opposite side of the object to be plated with respect to the anode, and sends out the plating solution toward the object to be plated through the anode. Item 2. The electrolytic plating apparatus according to Item 1. 3. The electrolysis according to claim 1, wherein said anode comprises a mesh electrode, and said blowing means and said suction means are arranged on a side of said anode opposite to said object to be plated. Plating equipment. 4. The plating solution according to claim 1, wherein the suction means is disposed on the opposite side of the object to be plated with respect to the anode, and the blowing means is provided adjacent to the anode, the plating solution containing a metal cation. 2. The electrolytic plating apparatus according to claim 1, wherein the gas is drawn from the suction means and sent out from the blowing means toward the object to be plated.