JPH1025600A - Paddle rotation type plating method and plating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form metallic films having uniform film quality and film thickness on a round-shaped substrate by electroplating. SOLUTION: While a paddle 3 is kept rotated in a direction B around the center of the round-shaped substrate 2 on the surface on the round-shaped substrate 2 arranged near a cathode 1, currents are independently supplied to an auxiliary electrode 4 disposed along the outer periphery of the cathode 3 and the cathode 1. As a result, the metallic films having the uniform film quality and film thickness are formed circumferential on the round-shaped substrate 2. The differences in the film quality and film thickness from the center to the circumferential direction of the round-shaped substrate 2 are eliminated by adjusting the rate of currents value passing the cathode and the auxiliary electrode 4 and consequently, the metallic films having the uniform film quality and film thickness are formed over the entire part on the round-shaped substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for electroplating a metal film, and more particularly to a method and an apparatus for plating a metal such as a magnetic alloy such as permalloy and copper.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional plating apparatus for performing an electroplating method using a paddle for stirring a plating. This figure is a simplified version of FIG. 3 described in Japanese Patent Application Laid-Open No. Sho 61-170591 and FIG. 6 described in Japanese Patent Application Laid-Open No. 61-177392. This electroplating method is performed using an electroplating apparatus including a plating tank 6, a cathode 1, an anode 5, a round substrate 8, a paddle 3, and a motor 7. The paddle 3 is provided with the paddle 3 in the plating tank 6 and is connected to the motor 7 by link-crank means 9 extending across the edge of the plating tank 6. Plating tank 6
A current flows between the cathode 1 and the anode 5 provided therein, and the cathode 1
When the metal film is electrically plated on the round substrate 8 arranged near the motor, first, the motor 7 is started, and the rotation of the shaft of the motor 7 is changed to reciprocating motion by the link-crank means 9 to make the paddle 3. To communicate. The paddle 3 performs plating on the surface of the round substrate 8 while reciprocating in the direction A in the drawing.

[0003]

In the above-mentioned prior art, the moving speed of the paddle during the turning of the reciprocating motion of the paddle becomes small, and the paddle cannot sufficiently stir the plating solution. Therefore, an irregular film quality is formed on the round substrate along the moving direction of the paddle, resulting in a difference in the overall film thickness. As described above, it is extremely difficult to form a metal plating film having a uniform film quality and thickness on a round substrate only by the reciprocating motion of the paddle. Therefore, for example, in the case of a magnetic alloy of a thin-film magnetic head, a plating method that can achieve uniform quality of products on a substrate is required, such as a magnetic head having more uniform electromagnetic conversion characteristics on a substrate. .

An object of the present invention is to provide a paddle rotating plating method capable of forming a metal film having a uniform film quality and thickness on a substrate in order to solve the above-mentioned problems.

It is another object of the present invention to provide a paddle rotary plating apparatus capable of forming a metal film having a uniform film quality and thickness on a substrate.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a paddle rotary plating method according to the present invention, that is, to provide an auxiliary electrode having an outer diameter smaller than the inner diameter of a plating tank along the outer periphery of a cathode, and to provide A rod-shaped paddle with a length smaller than the inner diameter of the plating tank is provided, and the paddle is rotated and moved on the surface of the round substrate, on the auxiliary electrode, and on the cathode. To supply current,
By adjusting the ratio of the two currents, a paddle rotating plating method characterized in that a metal film having a uniform film quality and thickness is formed on a round substrate.

It is preferable that the heights of the upper surfaces of the substrate, the cathode, and the auxiliary electrode are all the same. Furthermore, it is preferable that the center of the substrate, the center of the cathode, and the center of the auxiliary electrode have the same central axis. More preferably, the rotation axis of the paddle passes through the center of the round substrate.

Further, when adjusting the ratio to the current flowing through the cathode, the difference in film quality between the center of the metal film formed on the substrate and the outer peripheral direction thereof may be minimized. Alternatively, the difference in thickness between the center of the metal film formed on the substrate and the outer peripheral direction may be adjusted to be minimum.

Further, regarding the shape, the outer diameter of the auxiliary electrode is preferably substantially the same as the outer diameter of the anode. Preferably, the length of the paddle is substantially the same as the outer diameter of the auxiliary electrode. More preferably, the cross-sectional shape of the paddle is triangular. The upper surface of the paddle may be a smooth surface, and the lower surface of the paddle is more preferably parallel to the surface of the substrate.

According to the plating method of the present invention, an auxiliary electrode is provided along the outer periphery of a cathode, and a paddle for stirring a plating solution is rotated on a round substrate placed on the surface of the cathode around the center of the round substrate. Meanwhile, a current is independently supplied to the auxiliary electrode and the cathode.

Furthermore, when the paddle for stirring the plating solution is rotated around the center of the round substrate during plating, the paddle is uniformly distributed in the circumferential direction of the round substrate from the center to the outer peripheral direction due to the relative speed difference between the paddles. There is a gradually changing difference between the film quality and the film thickness. The difference between the film quality and the film thickness is eliminated by adjusting the ratio between the auxiliary electrode provided along the outer periphery of the cathode and the current flowing independently to the cathode. Therefore, a metal film having a uniform film quality and thickness is formed on the round substrate.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the paddle rotary plating method and paddle rotary plating apparatus of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing a plating apparatus for carrying out the paddle rotary plating method of the present invention. The round substrate 2 is arranged in the circular cathode 1 provided on the circular bottom surface of the cylindrical plating tank 6, and the donut-shaped auxiliary electrode 4 is arranged along the outer periphery of the circular cathode 1. A circular anode 5 is arranged in parallel with the cathode 1 in a plating tank 6 above the anode. At this time, the surface height of the cathode 1, the surface height of the round substrate 2, and the surface height of the auxiliary electrode 4 are all arranged to be the same. The anode 5 and the plating tank 6 are connected to the auxiliary electrode 4
It is a circle slightly larger than the outside dimensions of. In addition, the round substrate 2
, The center of the circular cathode 1 and the center of the donut-shaped auxiliary electrode 4 are the same, and the center of the paddle 3 is preferably disposed immediately above the center. Paddle 3
Is rotated by a motor 7 which is an external driving device of the plating tank 6.

FIG. 2 is a top perspective view showing the positional relationship between the cathode 1 and the paddle 3 of the plating apparatus shown in FIG. A paddle 3 for stirring the plating solution is installed in parallel with the surfaces of the circular cathode 1, the round substrate 2 and the donut-shaped auxiliary electrode 4, and the paddle 3 is a motor outside the plating tank around the center of the round substrate 2. 7 rotates in the B direction in the figure. The paddle 3 is rod-shaped, has a substantially triangular cross section, and is disposed so that its base is substantially parallel to the surface of the round substrate 2, its apex is as smooth as possible, and its length is the outer diameter of the auxiliary electrode 4. It is good that the diameter is almost the same. The center of the paddle 3 is preferably located on the axial extension of the motor 7.

Next, when a metal film is actually formed on the round substrate 2 by the plating apparatus that performs the paddle rotary plating method of the present invention, the plating bath 6 is filled with a plating solution, and the motor 7 is used. While rotating the paddle 3 in the direction B in FIG. 2, between the anode 5 and the cathode 1, and between the anode 5 and the auxiliary electrode 4.
And an independent current is supplied between them. In the plating method of the present invention, a donut-shaped auxiliary electrode 4 is provided along the outer periphery of the circular cathode 1, and plating is performed on a circular substrate 2 disposed on the surface of the circular cathode 1 with the center of the circular substrate 2 as an axis. A current is independently supplied to the auxiliary electrode 4 and the cathode 1 while rotating the paddle 3 for liquid stirring. When plating, round substrate 2
When the paddle 3 for stirring the plating solution is rotated around the center of the round substrate 2 as an axis, the paddle 3 is uniformly distributed in the circumferential direction of the round substrate 2 due to the relative speed difference between the paddles 3 and gradually from the center to the outer direction. There is a change in film quality and thickness that varies. The difference between the film quality and the film thickness is eliminated by flowing a current independently to the cathode 1 and the auxiliary electrode 4 provided along the outer periphery of the cathode 1 and adjusting the ratio of the two currents. That is, the current flowing through the auxiliary electrode 4 is made smaller than the current flowing through the cathode 1. As a result, a metal film having a uniform film quality and thickness is formed on the round substrate. The ratio of the respective current values is adjusted so that the difference in film quality from the center to the outer peripheral direction of the metal plating film formed on the round substrate 2 is minimized.

[0016]

According to the paddle rotation type plating method and paddle rotation type plating apparatus of the present invention, by rotating the paddle, uniform film quality and thickness can be formed in the circumferential direction of the round substrate, and the cathode and the cathode can be formed. By adjusting the value of the current flowing through the auxiliary electrode, the difference between the film quality and the film thickness from the center to the outer periphery of the round substrate can be eliminated. Therefore, a metal film having a uniform film quality and thickness can be formed on a round substrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a plating apparatus for performing a paddle rotary plating method of the present invention.

FIG. 2 is a top perspective view showing a positional relationship between an anode and a paddle in FIG. 1;

FIG. 3 is a cross-sectional view of a plating apparatus that performs a conventional plating method.

[Explanation of symbols]

 Reference Signs List 1 cathode 2 round substrate 3 paddle 4 auxiliary electrode 5 anode 6 plating tank 7 motor 8 substrate 9 link-crank means

Claims (12)

[Claims] 1. A method in which a circular substrate is supported on a horizontal circular cathode provided on a bottom surface of a cylindrical plating tank, and a plating solution is moved along a surface of the cathode and the round substrate. In the plating method of energizing the cathode and an anode provided in parallel above the cathode, an auxiliary electrode having an outer diameter smaller than the inner diameter of the plating tank is provided along the outer periphery of the cathode, On the cathode, a rod-shaped paddle having a length smaller than the inner diameter of the plating tank is provided, and while rotating the paddle, the surface of the round substrate, the auxiliary electrode, and the cathode are moved, A current is independently supplied to the auxiliary electrode and the cathode, and a metal film having a uniform film quality and thickness is formed on the round substrate by adjusting a ratio of the two currents. Paddle rotating plating method. 2. The paddle rotary plating method according to claim 1, wherein the heights of the upper surfaces of the round substrate, the cathode, and the auxiliary electrode are all the same. 3. The paddle rotary type according to claim 1, wherein the center of the round substrate, the center of the cathode, and the center of the auxiliary electrode have the same central axis. Plating method. 4. The paddle rotary plating method according to claim 1, wherein a rotation axis of said paddle passes through a center of said round substrate. 5. The metal film formed on the round substrate has a minimum difference in film quality between a center and an outer peripheral direction thereof.
The paddle rotary plating method according to any one of claims 1 to 4, wherein a ratio between a current flowing through the auxiliary electrode and a current flowing through the cathode is adjusted. 6. The metal film formed on the round substrate has a thickness difference between a center and an outer peripheral direction thereof, which is minimized.
The paddle rotary plating method according to claim 1, wherein a ratio between a current flowing through the auxiliary electrode and a current flowing through the cathode is adjusted. 7. The paddle rotary plating method according to claim 1, wherein an outer diameter of said auxiliary electrode is substantially the same as an outer diameter of said anode. 8. The paddle rotary plating method according to claim 1, wherein a length of said paddle is substantially equal to an outer diameter of said auxiliary electrode. 9. The paddle rotary plating method according to claim 1, wherein a cross-sectional shape of said paddle is substantially triangular. 10. The paddle rotary plating method according to claim 1, wherein an upper surface of said paddle is a smooth surface. 11. The paddle rotary plating method according to claim 1, wherein a lower surface of said paddle is parallel to a surface of said round substrate. 12. A round substrate is supported on a horizontal circular cathode provided on the bottom surface of a cylindrical plating tank, and while a plating solution is moved along the surface of the cathode and the round substrate, In a plating apparatus that conducts electricity between the cathode and an anode provided in parallel above the cathode, an auxiliary electrode having an outer diameter smaller than the inner diameter of the plating tank is provided along an outer periphery of the cathode, On the cathode, a rod-shaped paddle having a length smaller than the inner diameter of the plating tank is provided, and while rotating the paddle, the surface of the round substrate, the auxiliary electrode, and the cathode are moved, A current is independently supplied to the auxiliary electrode and the cathode, and a metal film having a uniform film quality and thickness is formed on the round substrate by adjusting a ratio of the two currents. Paddle rotary plating equipment.