JPH0578885A - Electroplating apparatus - Google Patents

Abstract

PURPOSE:To form a high quality plating film by electroplating at a high speed. CONSTITUTION:An electric conductive body 3 to be plated and an electrode 4 are immersed in a plating soln. 2 in a plating tank 1 so that they confront each other. A DC power source 6 is connected to the body 3 to be plated and the electrode 4 so that the body 3 acts as the cathode and the electrode 4 acts as the anode. Magnetic field generators 8 for applying a magnetic field H are arranged near the body 3 to be plated. Metal ions 5 are trapped near the body 3 by the magnetic field H.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrolytic plating apparatus. More specifically, the present invention relates to an electroplating apparatus that performs plating on an object to be plated by applying a voltage between the object to be plated immersed in a plating solution and an electrode.

[0002]

2. Description of the Related Art FIG. 3 shows a schematic structure of a conventional electrolytic plating apparatus B. In this electroplating apparatus B, the electroconductive object 3 to be plated is contained in the plating solution 2 held in the plating tank 1.
A DC power source 6 is externally connected to the object to be plated 3 and the electrode 4 so that the object to be plated 3 serves as a cathode and the electrode 4 serves as an anode.

However, when an electric current is supplied from the DC power source 6, the metal ions 5 in the plating solution 2 are attracted to and moved by the object 3 to be plated, and the metal ions 5 and the DC power source 6 on the surface of the object 3 to be plated. The supplied electrons combine to deposit the plating metal.

However, in such an electrolytic plating apparatus B, as the metal ions 5 are deposited on the surface of the object 3 to be plated and the metal ions 5 are consumed, the object 3 to be plated is consumed.
The concentration of metal ions in the vicinity of was decreased, which caused a decrease in plating rate.

FIG. 4 shows a schematic structure of another conventional electrolytic plating apparatus C. The electrolytic plating apparatus C is provided with a jet flow generator 7 such as a stirring blade for stirring the plating liquid 2 by a jet flow in the plating tank 1.

However, the plating solution 2 is agitated by the jet flow, and the plating solution 2 rich in the metal ions 5 is constantly supplied to the region where the metal ions 5 are diluted in the vicinity of the object 3 to be plated, to be plated. The decrease of the metal ion concentration in the vicinity of the object 3 is prevented.

However, in this jet type electrolytic plating apparatus C, since the plating solution 2 is agitated, a flow velocity distribution and vortices of the plating solution 2 are generated, and the thickness and quality of the plating film are affected by the vortex distribution. Unevenness and scratches on the surface of the plating film were likely to occur.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above conventional examples, and an object of the present invention is to prevent a decrease in plating rate due to a decrease in metal ion concentration and to prevent plating. An object of the present invention is to provide an electrolytic plating apparatus capable of preventing variations in film thickness, film quality and the like.

[0009]

In the electrolytic plating apparatus of the present invention, an object to be plated and an electrode are immersed in a plating solution, and a voltage is applied between the object to be plated and the electrode to plate the object to be plated. The electrolytic plating apparatus is characterized by including a magnetic field generator for applying a magnetic field near the object to be plated.

[0010]

When a magnetic field is applied near the object to be plated by the magnetic field generator, metal ions are successively trapped near the object to be plated, and the concentration of metal ions near the object to be plated increases. Therefore, the metal ion concentration in the vicinity of the object to be plated can always be kept high, and a decrease in plating rate can be prevented. Moreover, since only the metal ions can be moved by the magnetic field and the plating solution itself is not agitated, flow velocity distribution of the plating solution, vortices, etc. do not occur, and the film thickness and film quality of the plating film can be made uniform.

[0011]

FIG. 1 shows a schematic structure of an electrolytic plating apparatus A according to an embodiment of the present invention. Reference numeral 1 denotes a plating tank for holding a plating solution 2 in which the conductive object 3 and the electrode 4 are immersed in the plating solution 2 so as to face each other.
An external DC power source 6 is connected to the electrodes 4 and 4 so as to serve as a cathode and an anode, respectively. A magnetic field generator 8 such as a permanent magnet or an electromagnet for applying a magnetic field H to the plating solution 2 is provided near the object 3 to be plated outside the plating tank 1. The magnetic field H generated by the magnetic field generator 8 is orthogonal to the direction of the electric field acting between the object to be plated 3 and the electrode 4, and is parallel to the surface of the object to be plated 4.

In the plating solution 2, the metal ions 5 randomly move (Brownian motion) while colliding with other molecules and ions in the solution. Then, when the randomly moving metal ions 5 enter the magnetic field H, they move in a spiral motion (cyclotron motion) as shown in FIG. Even if it collides with other molecules or ions on the way and the direction is changed, it still moves while spiraling in the magnetic field H.
As a result, it becomes difficult for the metal ions 5 once trapped in the magnetic field H to leave the magnetic field H. In this way, when the metal ions 5 are successively captured in the magnetic field H, the metal ion concentration increases near the magnetic field H, that is, in the vicinity of the object 3 to be plated, and the metal ions 5 sufficient for plating are supplied. Therefore, the metal ions 5 in the plating solution 2 are not included in the plating target 3
Even if it is attracted to the surface of the object 3 to be plated by the electric field between the electrode 4 and the electrode 4, the metal plating concentration does not decrease. Further, the spiral movement of the metal ions 5 causes the metal ions 5 to be uniformly stirred in the vicinity of the object 3 to be plated.

However, since the metal ion concentration of the plating solution 2 is less likely to decrease near the object 3 to be plated, the decrease in plating speed is prevented and the plating film can be formed at high speed. In addition, since the metal ions 5 are only moved by the magnetic field H and the plating solution 2 itself does not move, a flow velocity distribution and vortices of the plating solution 2 do not occur, and a plating film having a uniform film thickness and film quality is formed. You can

In the above embodiment, the magnetic field generator is arranged so that the magnetic field direction is parallel to the surface of the object to be plated (perpendicular to the electric field), but a magnetic field is applied near the object to be plated. If so, it does not matter in other directions.
For example, the magnetic field generator may be arranged so that the magnetic field direction is perpendicular to the surface of the object to be plated (parallel to the electric field).

[0015]

According to the present invention, since the metal ions can be trapped by the magnetic field, the vicinity of the object to be plated can be always rich in metal ions, and the reduction of the plating rate can be prevented. Further, unlike the method of stirring the plating solution, the flow rate distribution of the plating solution, vortices, etc. do not occur, it is possible to reduce variations in the film thickness and film quality of the plating film, and scratches such as scratches do not occur. Therefore, a high quality plating film can be formed at high speed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrolytic plating apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing spiral motion of metal ions in a magnetic field in the example of the same.

FIG. 3 is a schematic configuration diagram of an electrolytic plating apparatus according to a conventional example.

FIG. 4 is a schematic configuration diagram of an electrolytic plating apparatus according to another conventional example.

[Explanation of symbols]

 2 plating liquid 3 object to be plated 4 electrode 8 magnetic field generator

Claims (1)

[Claims] 1. An electrolytic plating apparatus for immersing an object to be plated and an electrode in a plating solution and applying a voltage between the object to be plated and the electrode to plate the object to be plated, wherein a magnetic field is present near the object to be plated. An electrolytic plating apparatus comprising a magnetic field generator for applying a magnetic field.