JPS63176500A - Shielding plate for electroplating - Google Patents

Abstract

PURPOSE:To easily and finely uniformize the current density for various materials to be plated by the title shielding plate obtained by laminating plural free-to-slide plates having through holes in a plating soln., and changing the numerical aperture by shifting the through holes. CONSTITUTION:The shielding plate 10 for electroplating provided with through holes is inserted in the plating soln. to uniformize the current density for the material to be plated. The two perforated plates 12 and 14 respectively having through holes 20 and 22 are laminated to form the shielding plate 10, and both plates can be rotated by a cylinder shaft 24 around the center holes 16 and 18 and made free to slide. The rear plate 14 of the shielding plate 10 is rotated with respect to the front plate 12 and transferred from the position where the through hole 22 is aligned with the through hole 20 to the position where the hole 22 is shifted from the hole 20. By this method, the numerical aperture can be changed in accordance with the kind of material to be plated and other factors, and the current density for the material to be plated is adjusted.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a shielding plate for electroplating.

(Conventional technology) In electroplating, especially in the case of rack plating in which objects to be plated are hung on racks, objects to be plated suspended at the periphery of the rack are more sensitive than objects to be plated suspended in the center of the rack. Plating also tends to be thick.

This tendency is due to the fact that in a region where the object to be plated is suspended, the current density tends to be distributed higher at the edge of the region than at the center of the region.

In order to prevent variations in plating thickness due to such variations in current density distribution, conventionally, as shown in Fig. 6, a through hole 3o is provided in the center between the anode and the cathode, that is, the object to be plated. By inserting a shielding plate 32 into the plating solution to shield the surrounding area, the current density distribution is made as uniform as possible.

(Problems to be Solved by the Invention) However, even the conventional shielding plate for electroplating described above has the following problems.

That is, there are various factors contributing to the variation in current density distribution, such as the composition of the plating solution, the distance to the electrode plate, and the area of the electrode plate. It was also found that variations in the current density distribution were observed due to differences in the type of the object to be plated (especially size, shape, surface area, etc.). Under such conditions, the former factors such as the composition of the plating solution can be avoided by carefully selecting the bath composition and managing the bath. However, the latter factor, which is caused by different types of objects to be plated, is difficult to control.

] Therefore, in the past, shielding plates with different porosity ratios were prepared for each type of object to be plated, and the shielding plates were replaced each time the type was different. .

However, this requires a lot of effort for replacement, and it is also uneconomical and complicated to prepare different shielding plates for each type of object to be plated.

Therefore, the present invention has been made to solve the above problems, and its purpose is to provide a shielding plate for electroplating that can vary the porosity depending on the type of object to be plated and other factors. be.

(Summary of the Invention) According to the shielding plate for electroplating according to the present invention for the above-mentioned purpose, the shielding plate for electroplating is provided with a through hole and is inserted into a plating solution to equalize the current density to the object to be plated. The invention is characterized in that a plurality of perforated plates having through holes are slidably stacked one on top of the other so that the perforation ratio can be varied by shifting the through holes at the sliding position.

(effect) The operation of the embodiment shown in FIG. 1 will be explained.

The back plate 14, which is a perforated plate, is rotated with respect to the front plate 12, which is a perforated plate, from a position where its through holes 18 are aligned with the through holes 16 to a position where they are displaced as shown in the figure. The opening ratio of the holes 18 can be varied in various ways. This changes the shielding rate in various ways, making it possible to adjust the current density to the object to be plated.

(Embodiment) A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a rear view of a shielding plate 10 for electroplating according to the present invention, and FIG. 2 shows a plan view thereof.

The electroplating shielding plate 10 according to this embodiment has a top plate 12
On the other hand, a back plate 14 is superimposed on the back plate 14 so as to be rotatable about the center thereof. A relatively large diameter through hole 16.18 of the same size is bored in the center of the front plate 12 and the back plate 14, and four through holes 20.22 are formed at the same radial position (six directions in the figure). They are also drilled in the same position and size.

, the central through hole 16.18 is in the radial position,
The cylindrical shaft 24 that stands up from the edge of the through hole 18 of the back plate 14 is connected to the top plate 12.
The tip of the cylindrical shaft 24 that fits into the through hole 16 and projects from the surface of the back plate 12 is bent outward, so that the cylindrical shaft 24 is rotatable about the cylindrical shaft 24 as an axis. Needless to say, the rotation mechanism of the front plate 12 and the back plate 14 is not limited to the above-mentioned example. Various mechanisms may be employed, such as providing a (not shown) on the top plate 12 and rotating it.

Note that it is preferable to provide an appropriate stopper mechanism so that the front plate 12 and the back plate 14 can be stopped at any rotational position. The stopper mechanism can be constructed, for example, so that the front plate 12 and the back plate 14 engage with each other in a concave and convex manner (not shown).

This embodiment is configured as described above.

The shielding plate IO is used by being inserted into the plating solution so as to be positioned between the electrode plate and the object to be plated, as in the conventional case.

At that time, the back plate 14 is attached to the front plate 12 as shown in FIG.
When the through holes 20 and 22 are rotated and used so that they overlap with each other, the through holes 20.22 on the edge side are It can be used in such a manner that the porosity becomes smaller as it goes outward.

Further, it is possible to continuously vary the difference in the porosity from the center to the edge by changing the angle of rotation.

The setting of the aperture ratio (rotation angle of the back plate 14 with respect to the front plate 12) on the center and edge sides is selected depending on the type of the object to be plated. To determine which porosity is optimal for a particular object to be plated, it is necessary to determine in advance the variation in plating thickness of the object to be plated with respect to various porosity ratios.
It is best to use the pore area within the optimum range.

31st! i shows an example of experimentally determined variations in plating and thickness at various rotation angles of the back plate 14 relative to the top plate 12 for product A and product B.
In the example, a rotation angle of approximately 2° was optimal for product A, and a rotation angle of approximately 3° was optimal for product B.

It should be noted that the causal relationship with the aperture ratio (rotation angle) of the shielding plate 10 can also be determined for other factors of current density distribution fluctuations (variations in plating thickness), such as changes in the composition of the plating solution and the distance from the electrode plate. By experimentally elucidating, not only different products but also
It can be used with an optimal porosity even in accordance with different plating solution compositions, and more detailed plating management can be performed.

In the above embodiment, the through holes 20 and 22 in the drawings are circular, but the shape may be elliptical or polygonal.
Furthermore, the size (especially in the radial direction) does not necessarily have to be the same.

Furthermore, in the mechanism that rotates the back plate 14 with respect to the front plate 12 while being guided by its outer periphery as described above,
The central apertures 16.18 may be non-circular so that the aperture ratio between the central apertures 16.18 can be varied.

FIGS. 4(a) and 4(b) show other embodiments.

In this embodiment, the back plate 14 is connected to the rail 26 with respect to the front plate 12.
26 so that it can slide horizontally or vertically.

Also in this embodiment, the aperture ratio can be varied between the central portion and the edge portions of the shielding plate 10, respectively.

FIGS. 5(a) and 5(b) show still another embodiment.

In this embodiment, the through hole 18 in the center of the back plate 14 is connected to the cylindrical shaft 24.
The outer diameter of the plate 14 is made larger than the outer diameter of the plate 14 so that the plate 14 can be displaced over a predetermined range in any direction with respect to the top plate 12, and can also rotate with respect to the top plate 12. ing. For this purpose, the bent portion of the cylindrical shaft 24 shown in FIG. 1 is formed wide in this embodiment as shown.

In this embodiment, the back plate 14 is further provided with a function of being movable in any direction relative to the front plate 12.
The porosity of the through holes in each part can be further varied.

In each of the above embodiments, two perforated plates were used, a front plate and a back plate, but of course three or more perforated plates could be used and stacked one on top of the other. In this case, for example, 2 holes for the first perforated plate.
Various sliding directions can be selected, such as making the third perforated plate horizontally slidable and the third perforated plate rotatable.

Note that in the present invention, the term "slide" is a concept that includes both movement in the horizontal direction or any direction, and rotational movement.

Although various preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments, and changes in the detailed shape, configuration, arrangement, etc. may be made within the scope of the spirit of the present invention. It goes without saying that this invention belongs to the present invention.

(Effects of the Invention) As described above, according to the shielding plate for electroplating according to the present invention, the perforation ratio of the holes can be varied continuously by multiple perforated plates being slidably overlapped. Optimal opening depending on the type of material to be plated! It can be used with high porosity, and the plating thickness can be made uniform.

In addition, even if the current density distribution changes due to changes in plating conditions such as changes in the composition of the plating solution, it is possible to make the current density uniform by changing the aperture ratio, making plating management even more fine-grained (and Now it can be done easily.

[Brief explanation of the drawing]

FIG. 1 is a rear view showing a preferred embodiment of the shielding plate for electroplating according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a front and back side of the shielding plate shown in FIG. 1. Graph showing variations in plating thickness with respect to changes in plate rotation angle, Figure 4(a), (
b) and FIGS. 5(a) and 5(b) respectively show other embodiments, with (a) being a rear view and (b) being a plan view. FIG. 6 is an explanatory diagram of a state in which a conventional shielding plate is inserted into a plating solution. 10... Shielding plate for electroplating, 12... Top plate, 14... Back plate, 16... Through hole, 18... Through hole, 20. 22... Through hole, 24
...Cylinder shaft, 26...Rail.

Claims (1)

[Claims] 1. A shielding plate for electroplating that is provided with through holes and inserted into a plating solution to equalize the current density to the object to be plated, comprising: a plurality of perforated plates each having through holes; , electroplating shielding plates that are slidably stacked one on top of the other in order to make the porosity variable by shifting the through holes in the sliding position. 2. The shielding plate for electroplating according to claim 1, which is formed by stacking a plurality of perforated plates so as to move in any direction. 3. The shielding plate for electroplating according to claim 1, comprising a plurality of perforated plates stacked one on top of the other in a rotating manner.