JP2008266670A - Electroplating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroplating apparatus in which even the inside of a fine through hole such as that in a printing circuit is satisfactorily plated even at a high speed plating and the occurrence of uneven plating or burnt plating is suppressed. <P>SOLUTION: In the electroplating apparatus, an anode 3 and a cathode 1 are arranged inside a plating bath 5, a shield plate 6 for current dispersion is arranged between the anode 3 and the cathode 1 and a plate-like blade 7 is arranged between a cathode and a shield plate for current dispersion and a movement mechanism for moving the plate-like blade 7 back and forth parallel to the cathode is provided. The plate-like blade 7 is arranged at a tilt to the cathode so as to give the flow speed to a plating solution in the cathode direction by the back and forth movement of the plate-like blade 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electroplating apparatus. In particular, the present invention relates to the field of fine circuit processing for circuits where a dense plating layer is required, such as a printed circuit, but in addition to other fields such as various plating and chemical conversion treatment of metal plates, batteries, etc. Application is also possible.

  In recent years, in the manufacture of printed circuits such as flexible printed circuits (hereinafter referred to as FPC), ultrafine wiring processing is increasingly required. In the printed circuit, in addition to deep holes and channels, there are through holes called through holes. However, when an electric circuit is formed by electrolytic copper plating or the like, plating is performed in a short time with a large current, so that the plating film is mainly formed only on the surface of the substrate and is difficult to form inside the through hole.

  Furthermore, from the viewpoint of productivity, it has been conventionally required to increase the plating speed (hereinafter also referred to as high-speed plating), but as the plating speed is increased, the plating formation inside the through hole becomes worse. was there.

  Also, in electroplating, current tends to concentrate on the periphery of the plated substrate, so the thickness of the plating layer on the periphery is thicker than that on the center of the plated substrate, and the plating is burnt on the periphery. It was easy to occur.

  As a method for improving the formation of the plating inside the through hole, for example, a method of improving the plating formation inside the through hole by causing a jet of a plating solution by a pump and guiding the jet into the through hole (Patent Document 1). ) And a method of improving the plating formation inside the through hole by providing ultrasonic elements between the anode and the cathode to generate ultrasonic waves, forming cavities inside the through holes, and assisting the diffusion of copper ions. (Patent Document 2) and the like have been proposed.

However, the method of causing the plating solution to flow with the pump described in Patent Document 1, an example of which is shown in FIG. 3, has the following problems.
That is, in FIG. 3, the cathode 1 as a plating substrate has a through hole 2 and is fixed to the cathode frame 8. The plating solution pressurized by a pump (not shown) is discharged from the pipe 10. However, when the diameter of the pipe 10 is small, the flow of the jet liquid is not uniform with respect to the cathode 1 as shown by an arrow as shown in FIG. On the other hand, when the diameter of the pipe 10 is large, a large pressure is applied to the central portion of the cathode 1 as shown in FIG. 3B. Especially in the plating on the FPC board, the cathode 1 (that is, plating) as shown in the figure. There is a risk that the substrate) will bend.
Furthermore, the method of generating a plating solution jet with a pump is effective for a through hole having a large diameter of several hundred microns or more, but for a minute through hole such as a printed circuit, the liquid flux Because of the diffusion, there was a problem that the effect was not recognized.

Further, in the method of generating cavities inside through-holes by ultrasonic waves disclosed in Patent Document 2, the anode and cathode are not connected to the substrate periphery for the purpose of avoiding current concentration on the periphery of the substrate when performing high-speed plating. A plate having a large number of holes in between (hereinafter referred to as a current dispersion shielding plate) is arranged to make the potential distribution uniform. However, since the current transmission shielding plate obstructs the transmission of ultrasonic waves and it is difficult to generate cavities up to the through hole, it cannot be said that it is an effective method for sufficiently plating the inside of the through hole. . Further, in the case of high-speed plating, the occurrence of non-uniform plating or burnt plating cannot always be sufficiently suppressed only by arranging a current dispersion shielding plate between the anode and the cathode.
WO2004-009879 JP-T-2005-524864

  In view of the above-described circumstances, the present invention can sufficiently plate the inside of a fine through hole such as a printed circuit even in high-speed plating, and at the same time, suppresses the occurrence of non-uniform plating and charring plating. It is an object of the present invention to provide an electroplating apparatus that can be used.

As a result of diligent research, the present inventor has arranged a plate-like blade and a current dispersion shielding plate between the anode and the cathode, and further moved the plate-like blade back and forth in parallel with the cathode to cause the plating solution to move toward the cathode. By using an electroplating device that can provide a flow rate, even within high-speed plating, it is possible to perform sufficient plating even inside fine through-holes, and to prevent the occurrence of non-uniform plating and scorching plating. The headline and the present invention were completed.
Hereinafter, the invention of each claim will be described.

The invention described in claim 1
An anode and a cathode are disposed inside the plating solution storage tank,
A current distribution shielding plate is disposed between the anode and the cathode,
A plate-like blade is disposed between the cathode and the current distribution shielding plate, and
A reciprocating mechanism for reciprocating the plate blade in parallel with the cathode;
The electroplating is characterized in that the plate blade is disposed to be inclined with respect to the cathode so that the plate blade reciprocates to give the plating solution a flow velocity in the cathode direction. Device.

  In the invention of this claim, the plate-like blade having an inclination is reciprocated in parallel with the cathode, thereby repeatedly causing the plating solution to flow in the direction of the cathode to the inside of the minute through hole. Since the plating solution is permeated, sufficient plating can be applied to the inside of the through hole.

In the present invention, since the plate-like blade is disposed between the current dispersion shielding plate and the cathode, even if the current dispersion shielding plate is used together, unlike the conventional technique using ultrasonic waves, a fine through-hole is provided. The effect of being able to sufficiently plate up the inside of the hole is not impaired.
In addition, since the current distribution becomes uniform by using it together with the current dispersion shielding plate, sufficient plating can be uniformly applied to any through hole located in any of the cathodes (plating substrates). .

  Furthermore, it has been found that the occurrence of non-uniform plating and scorching plating can be further reduced by applying a cathode flow rate to the plating solution. Therefore, according to the present invention, it is possible to further suppress the occurrence of non-uniform plating and scorch plating even in high-speed plating, as compared with the case where a current dispersion shielding plate is simply used.

  In the invention of this claim, as long as the plate blade is reciprocated substantially parallel to the cathode, the reciprocating direction may be any of the vertical direction, the horizontal direction, and the oblique direction, Although not particularly limited, the horizontal direction is preferable because it is easy to arrange a motion mechanism for reciprocating the plate blade and to secure a space when the plate blade moves.

  In addition, the inclination of the plate blade with respect to the cathode may be any direction as long as it gives a flow rate in the cathode direction to the plating solution, is appropriately determined according to the reciprocating direction, and is not particularly limited. .

Further, the shape and number of the plate blades, the interval between the plate blades and the plating substrate, and the like are not particularly limited, and are appropriately determined according to the size of the plating substrate.
For example, regarding the shape, in order to give a uniform flow rate to the plating solution, a flat plate shape and a rectangular shape are preferable. Further, regarding the number of sheets, in order to give a uniform flow rate to the entire plating solution, a plurality of sheets are preferable.

  When a plurality of plate blades are arranged, if the shape, size, distance from the cathode and the angle and direction of the inclination with respect to the cathode are the same, and the reciprocating motion is simultaneously performed at the same speed, a uniform flow rate is given to the plating solution This is preferable. At this time, for example, if both ends of each plate blade are fixed and connected with a common support rod, a plurality of plate blades can be easily reciprocated simultaneously at the same speed.

  The flow rate applied to the plating solution can be appropriately determined in consideration of the speed at which the plate blade reciprocates, the angle and direction of inclination of the plate blade with respect to the cathode, and the like.

  An example of the arrangement of the plate blades is shown in FIG. FIG. 2 is a schematic diagram for explaining an embodiment of the present invention to be described later. In FIG. 2, a total of six plate-like blades 7 on both sides of the cathode 1 are arranged at an angle of 45 degrees with respect to the cathode 1 and reciprocate in the direction indicated by the bidirectional arrows. do.

Invention of Claim 2 is the said electroplating apparatus, Comprising:
The electroplating apparatus is characterized in that the plate blade, the current dispersion shielding plate, and the anode are disposed on both sides of the cathode.

  In the present invention, the plate-like blades arranged on both sides of the cathode are reciprocated so that the liquid flow is applied from both sides of the cathode, so that a large force from one direction is applied to the cathode surface. This does not occur, and the occurrence of bending in the cathode can be prevented. Furthermore, since the liquid flow is applied to the through hole from both sides, the plating solution can be more effectively penetrated into the through hole.

Invention of Claim 3 is said electroplating apparatus, Comprising:
The plate blade, the current distribution shielding plate, and the anode are arranged at symmetrical positions with the cathode interposed therebetween, and the plate blades are arranged in parallel to each other. Electroplating equipment.

In the present invention, the plate-like blades arranged at symmetrical positions with the cathode interposed therebetween are arranged in parallel with each other and reciprocated to apply a substantially uniform liquid flow from both sides of the cathode. The occurrence of bending at the cathode can be prevented more effectively.
Furthermore, the effect of penetrating the plating solution into the through hole is more remarkable.

  Note that it is preferable to synchronize the reciprocating motions of the plate blades on both sides, since the liquid flows on both sides of the cathode are symmetrical with each other, and the occurrence of bending at the cathode can be more effectively prevented.

Invention of Claim 4 is the said electroplating apparatus, Comprising:
The electroplating apparatus is characterized in that the plate blade is disposed at an angle of 45 degrees with respect to the cathode.

  In the invention of this claim, since the mounting angle of the plate blade is defined as 45 degrees, a liquid flow perpendicular to the cathode surface can be obtained by reciprocating in parallel with the cathode surface. preferable.

  By using the electroplating apparatus according to the present invention, even in high-speed plating, sufficient plating can be performed even inside the fine through-hole, and generation of non-uniform plating and scorching plating can be prevented.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following embodiment. Various modifications can be made to the following embodiments within the same and equivalent scope as the present invention.

  FIG. 1 is a schematic sectional view of an electroplating apparatus according to an embodiment of the present invention. In FIG. 1, the cathode 1 is placed in the center of the plating tank 5, and the anode 3 is arranged near the tank wall surfaces on both sides. Further, a current distribution shielding plate 6 having an infinite number of holes is disposed between the cathode 1 and the anode 3, and a plate blade 7 is provided between the current distribution shielding plate 6 and the cathode 1. Further, the cathode 1 is fixed by a cathode frame 8, and all of the above are immersed in the plating solution 4 in the plating tank 5.

The operation will be described with reference to FIG. FIG. 2 is a schematic view for explaining an embodiment of the present invention, and is a view of the plating apparatus as viewed from above. Note that FIG. 2 is a schematic diagram only, and the intervals among the anode 3, the current dispersion shielding plate 6, the plate blade 7, and the cathode 1 are not matched with those in FIG. 1.
The cathode 1 which is a plating substrate is given a negative charge through the cathode frame 8, and a positive charge is given to the anode 3 side, whereby the cathode 1 is plated.

After the metal ions are released from the anode 3 into the liquid, the metal ions are rectified by the numerous holes of the current dispersion shielding plate 6, and the potential distribution is made uniform. Thereafter, metal is deposited and plated at the cathode 1. However, when the cathode 1 has a fine through-hole 2, it is difficult to uniformly plate the inside of the through-hole 2, and thus a plate-like blade 7 is disposed between the current distribution shielding plate 6 and the cathode 1. .
In the example shown in FIG. 2, three plate blades 7 are arranged on both sides of the cathode 1, and the upper and lower ends of the three plate blades 7 are fixed to a common connecting rod (not shown). Has been.

  As shown in FIG. 2, when the plating apparatus is viewed from above, the plate blade 7 is provided with an angle of 45 degrees with respect to the cathode 1, and each of the three plate blades 7 disposed on both sides of the cathode 1. Is reciprocated in the horizontal direction parallel to the cathode 1 (the direction indicated by the bidirectional arrow in the figure), thereby repeatedly applying the flow rate in the direction of the cathode 1 to the plating solution as indicated by the arrow. As described above, each of the three plate blades is fixed to a common connecting rod and reciprocates at the same speed, so that a uniform and uniform flow rate can be given to the plating solution with respect to the cathode 1. .

  Due to the reciprocating motion of the plate-like blade 7, the liquid flow is uniform and substantially perpendicular to the cathode 1, so that the plating liquid can be uniformly penetrated into the through hole 2 without the liquid flow being dispersed. .

A plate-like blade (cathode 1, large size) having 200 μm through-holes 2 is disposed as shown in FIG. The current density is 3 A / dm ² and the reciprocating speed of the plate blade 7 is adjusted so that the flow rate of the plating solution is 10 km / h. Carried out. After the treatment, the cross section around the through hole 2 was observed to confirm the plating state. The film thickness distribution was 8.0 ± 1.9 μm, and the plating was uniformly applied to the inside of the through hole.

It is a schematic sectional drawing of the Example of this invention. It is a schematic diagram explaining the Example of this invention. It is a schematic diagram which shows the flow of the plating solution (jet liquid) in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cathode 2 Through hole 3 Anode 4 Plating solution 5 Plating tank 6 Current dispersion shielding plate 7 Plate blade 8 Cathode frame 10 Liquid flow pipe

Claims (4)

An anode and a cathode are disposed inside the plating solution storage tank,
A current distribution shielding plate is disposed between the anode and the cathode,
A plate-like blade is disposed between the cathode and the current distribution shielding plate, and
A reciprocating mechanism for reciprocating the plate blade in parallel with the cathode;
The electroplating is characterized in that the plate blade is disposed to be inclined with respect to the cathode so that the plate blade reciprocates to give the plating solution a flow velocity in the cathode direction. apparatus.   The electroplating apparatus according to claim 1, wherein the plate blade, the current distribution shielding plate, and the anode are disposed on both sides of the cathode.   The plate blade, the current dispersion shielding plate, and the anode are arranged at symmetrical positions with the cathode interposed therebetween, and the plate blades are arranged in parallel to each other. The electroplating apparatus according to claim 1 or 2.   The electroplating apparatus according to any one of claims 1 to 3, wherein the plate blade is disposed at an angle of 45 degrees with respect to the cathode.

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