JP4977046B2 - Edge overcoat prevention device and electroplating material manufacturing method using the same - Google Patents

Description

  The present invention relates to an apparatus for preventing edge overcoat when electroplating a material to be plated such as a copper foil for electromagnetic shielding and a method for producing an electroplating material using the same.

Electroplating is a method generally used as a surface treatment method for forming a metal film on the surface of a material to be plated, regardless of whether it is double-sided or single-sided. However, conventionally, a so-called edge overcoat, in which a current is concentrated on an end portion of a material to be plated such as a metal strip and a plating amount increases, has been a problem. Therefore, in order to prevent edge overcoat, a technique is disclosed in which an edge mask is opposed to the end of the metal strip to physically shield the plating current (see Patent Documents 1 and 2).
Further, a technique is disclosed in which an anode mask is provided at the end of the anode to physically shield the plating current (see Patent Document 3).
Furthermore, a technique is disclosed in which auxiliary electrodes are arranged in the vicinity of both ends of the metal strip, and the auxiliary electrode is connected to a power source having the same polarity as the metal strip (see Patent Document 4). With the auxiliary electrode, current is also divided between the main electrode and the auxiliary electrode, and current concentration at both ends of the metal strip can be prevented.

Japanese Utility Model Publication No. 60-117863 Japanese Patent Laid-Open No. 8-239796 JP-A-6-306695 Japanese Patent Laid-Open No. 62-202020

However, in the case of the method using the edge mask, it is necessary to bring the edge mask close to both ends of the material to be plated in order to achieve a sufficient effect, and the edge mask and the material to be plated collide due to meandering of the material to be plated. In addition, the material to be plated may be broken or wrinkled. In particular, when plating is performed on a thin copper foil (for example, 6 to 100 μm) copper foil or the like, bending is likely to occur.
Further, in the case of single-side plating that is applied to electroplating after laminating one side of a copper foil or the like in advance with a resin film, edge overcoat may not be prevented even if an edge mask is used, unlike double-sided plating. In other words, with double-sided plating or single-sided plating without laminating, the current from the anode goes not only to the opposite surface of the strip, but also to the backside of the strip via the outside of the edge mask, and current is consumed for plating on the backside. Is done. However, as shown in FIG. 11, when the back surface 200b of the strip is an insulator (for example, a resin laminate), the current sneaking into the back surface 200b passes through the inside of the edge mask 300 because the back surface 200b is not plated. The edge of the upper surface 200a is plated to produce an edge overcoat.
Note that arrows extending from the main electrode 100 in FIG. 11 indicate lines of electric force. Further, since the strip 200 is symmetric about the center line C in the width direction, only the left side of the center line is shown.

  Moreover, even when a method of covering the side edge and back surface of the anode (opposite surface opposite to the surface of the strip) with an anode mask is used, the edge overcoat may not be prevented when the above single-sided laminate is electroplated. . This is because the current flowing around the outside of the anode mask concentrates on the edge of the material to be plated and causes an edge overcoat.

On the other hand, in the case of the method using the auxiliary electrode, the edge overcoat can be effectively prevented by the effect of trapping the current concentrated on the edge portion. However, the plating film adhered to and grown on the auxiliary electrode may collide with the material to be plated, causing the material to be plated to bend or wrinkle, or the material to be plated may bite the plating film on the auxiliary electrode. . This is because, when plating is performed for a long time, the Sn plating film deposited on the auxiliary electrode extends toward the end portion of the strip, and the distance between the two is reduced to come into contact with the strip. In particular, when the above-described thin copper foil or the like is used as a material to be plated, yield is likely to be lowered due to bending or biting of a plating film.
In addition, although the technique of patent document 2 arrange | positions an auxiliary electrode (anode) inside an edge mask, in this method, since plating is performed from the auxiliary electrode so as to overlap with the main electrode, It is necessary to adjust the current of the auxiliary electrode according to the warp or meandering of the end of the material, and it is difficult to adopt as a practical method.

  That is, the present invention has been made to solve the above-mentioned problems, and prevents edge overcoat during electroplating, and also breaks or wrinkles the material to be plated due to contact with the plating film deposited on the auxiliary cathode. An object of the present invention is to provide an edge overcoat prevention device that suppresses the above-described phenomenon and eliminates the biting of the plating film into the material to be plated, and a method for producing an electroplating material using the device.

To achieve the above object, the edge overcoat prevention device of the present invention is used in electroplating the strip, and an insulating body which is disposed opposite the ends of the strip, across the insulator An auxiliary cathode disposed in the vicinity of the strip , and a part of the insulator extends inward from an end portion of the strip to form an edge mask covering the end portion, along the thickness direction of the strip , the outer peripheral edge of said auxiliary cathode is located inside the outer peripheral edge of the insulator.

Thus, when an insulator is disposed between the auxiliary cathode and the material to be plated ( strip) , not only the edge overcoat is prevented by the auxiliary cathode, but also the plating that is deposited on the auxiliary cathode because the insulator becomes an obstacle. The metal is prevented from growing and reaching (contacting) the material to be plated. Therefore, bending and wrinkling of the material to be plated due to contact with the plating metal adhered and grown on the auxiliary cathode are suppressed, and the material to be plated does not bite the plating film on the auxiliary cathode.
In particular, if the material to be plated is a thin material such as a copper foil, the strength is low, so that the material is easily broken and wrinkled, and the present invention is effective. In the case of a single-sided plating material, even if an edge mask is used, the current flows from the non-plating surface side to the edge of the material to be plated via the edge mask inside, resulting in an edge overcoat. The edge overcoat can be effectively prevented by consuming.
Furthermore, since the outer peripheral edge of the insulator projects outward from the outer peripheral edge of the auxiliary cathode, the growth direction of the plating metal deposited on the auxiliary cathode is directed away from the material to be plated. Therefore, the contact between the plating metal and the material to be plated is further prevented.

One side of the strip may be insulative.

You may have a space | interval adjustment means to adjust the space | interval of the said auxiliary cathode and the said strip , and / or a current adjustment means to adjust the electric current of the said auxiliary cathode.
If it does in this way, the effect which prevents edge overcoat and the effect which prevents the precipitation of the plating metal to an auxiliary cathode can be moderately reconciled. In addition, by adjusting the distance between the auxiliary cathode and the material to be plated and / or the current of the auxiliary cathode, an optimal current distribution without edge overcoat can be obtained.

Preferably, the current adjusting means is capable of adjusting the current of the auxiliary cathode independently of the current applied to the strip .
In this way, the plating current can be controlled more accurately by the auxiliary cathode, and the plating over the edge overcoat and the auxiliary cathode can be more effectively prevented. Further, since excessive current is prevented from flowing to the auxiliary cathode, consumption of metal ions in the plating solution is suppressed, and consumption of the plating solution is reduced.

Preferably, the auxiliary cathode is disposed opposite to both ends of the material to be plated, and the current adjusting means can adjust the current of each auxiliary cathode independently.
In this way, since the current densities of the auxiliary cathodes at both ends can be changed, it is possible to prevent the edge overcoat from occurring only at one end of the material to be plated due to meandering of the material to be plated.

It is preferable to provide an anode mask on the anode facing the strip.
In this case, by using the auxiliary cathode and the anode mask together, the current that the anode mask wraps around is reduced, so that the current density of the auxiliary cathode can be further reduced.
The current density of the auxiliary cathode may be set to 7 A / dm ² or more and lower than the current density of the strip.
You may adjust the space | interval of the said auxiliary cathode and the said to-be-plated material to 85 mm or less.

Method of manufacturing an electro-plating material of the present invention, respectively disposed an insulator to face the opposite ends of the strip, the edge mask covering the end portion part of the insulator extends inwardly from the end portion of the strip An auxiliary cathode is disposed on the opposite side of the strip across the insulator, and the outer peripheral edge of the auxiliary cathode is positioned on the inner side of the outer peripheral edge of the insulator along the thickness direction of the strip , The strip and the auxiliary cathode are electroplated on the strip as a cathode.

  According to the present invention, edge overcoat during electroplating is prevented, and bending or wrinkle of the plating material due to contact with the plating film deposited on the auxiliary cathode is suppressed, and the plating film is bitten by the plating material. Can be eliminated. In particular, the present invention is effective when plating a thin material such as a copper foil, which is a single-sided plating material laminated on one side with a resin film.

Hereinafter, an edge overcoat prevention device according to an embodiment of the present invention will be described.
FIG. 1 shows an example of the overall configuration of a continuous electroplating apparatus including an edge overcoat preventing apparatus according to an embodiment of the present invention. However, the edge overcoat prevention apparatus of the present invention can be applied to all plating apparatuses such as a horizontal type and a drum type in addition to the vertical type plating apparatus shown in FIG.
The continuous electroplating apparatus 50 includes a plating tank 45 containing a plating solution, an energizing roll 30 and an upper roll 34 on the plating tank 45, and a sinker roll 32 disposed in the plating tank 45, and the copper foil strip 20 is energized by the energizing roll. The copper foil strip 20 is continuously run from 30 to the upper roll 34 via the sinker roll 32, and is moved into and out of the plating tank 45. Further, the main electrode (anode) 10 is vertically arranged facing the outside of the copper foil strip 20 stretched between the energizing roll 30 and the sinker roll 32, and similarly between the upper roll 34 and the sinker roll 32. The other main electrode (anode) 10 is arranged vertically so as to face the outside of the copper foil strip 20 stretched between the two.

Then, the copper foil strip 20 serving as the cathode is electroplated by the main power source (rectifier) 5 connected between the energizing roll 30 and the main electrode (anode) 10. In this embodiment, the continuous electroplating apparatus 50 is configured to electroplate one side of the copper foil strip 20, and Sn is used as the main electrode (anode) 10, for example. Further, a resin (PET; polyethylene terephthalate) film is laminated on one surface (back surface) 20b of the copper foil strip 20, and copper is exposed on the surface 20a.
Further, an edge overcoat prevention device 6 is disposed in the vicinity of both ends of the copper foil strip 20 facing each main electrode 10 so as to face the both ends. The edge overcoat prevention device 6 includes an auxiliary cathode described later, and the auxiliary cathode becomes a cathode by an auxiliary power source (rectifier) 42 connected between the energizing roll 30 and the auxiliary cathode.
The edge overcoat prevention device 6 extends vertically along both ends of the copper foil strip 20 and protrudes outside the thickness of the copper foil strip 20. The lower end of the edge overcoat prevention device 6 extends downward from the lower end of the main electrode 10, and the upper end of the edge overcoat prevention device 6 floats above the plating solution surface.

FIG. 2 is a partial cross-sectional view of the edge overcoat preventing device according to the first embodiment of the present invention when the copper foil strip 20 is cut in the width direction along a plane parallel to the paper surface direction of FIG. Since the copper foil strip 20 is symmetrical with respect to the center line C in the width direction, only the region from the center line to the left end is shown.
In FIG. 2, the insulator 2 is disposed to face the left end of the copper foil strip 20, and the auxiliary cathode 4 is disposed on the opposite side of the copper foil strip 20 with the insulator 2 interposed therebetween. The insulator 2 and the auxiliary cathode 4 constitute an edge overcoat prevention device 6.
The insulator 2 has a U-shaped cross section, and the ends of two U-shaped extension portions 2L are located inside the copper foil strip end portion 20c, and cover the front and back surfaces of the end portion 20c, thereby providing an edge mask. Configure. The surface of the U-shaped base portion of the insulator 2 is perpendicular to the width direction (and end surface) of the copper foil strip 20.
The thick plate-like auxiliary cathode 4 is in close contact with the back surface of the U-shaped base portion of the insulator 2 (the surface opposite to the surface facing the copper foil strip 20), and the outer peripheral edge of the auxiliary cathode 4 is the U-shape of the insulator 2. It is located inside the outer peripheral edge of the base. The auxiliary electrode is characterized in that the outer peripheral edge is located inside the outer peripheral edge of the edge mask of the insulator 2 and is not affected by the shape and position of the edge mask.

Thus, when an insulator is arranged between the auxiliary cathode and the material to be plated (copper foil strip 20), not only the edge overcoat is prevented by the auxiliary cathode but also the insulator becomes an obstacle, so that the auxiliary cathode is used. The deposited plating film is prevented from growing and reaching (contacting) the material to be plated. Therefore, bending and wrinkle of the material to be plated due to contact with the plating film adhered and grown on the auxiliary cathode are suppressed, and the material to be plated does not bite the plating film on the auxiliary cathode.
In particular, if the material to be plated is a thin material such as a copper foil, the strength is low, so that the material is easily broken and wrinkled, and the present invention is effective. In the case of a single-sided plating material, as described in FIG. 9 above, even if an edge mask is used, the current flows from the non-plating surface side to the edge of the material to be plated via the edge mask inside, and the edge overcoat However, edge overcoat can be effectively prevented by consuming current at the auxiliary cathode.

Furthermore, in the present invention, since the outer peripheral edge of the insulator projects outward from the outer peripheral edge of the auxiliary cathode, the growth direction D of the plating film (electrodeposited grains, etc.) deposited on the auxiliary cathode is separated from the material to be plated. Head in the direction Therefore, the contact between the plating film and the material to be plated is further prevented.
The shape of the auxiliary cathode 4 is not particularly limited. For example, the auxiliary cathode 4 may be cylindrical, rod-shaped, foil-shaped, on a plate, or the like. The smaller the volume of the auxiliary cathode 4 is, the smaller the amount of plating deposited on the auxiliary cathode 4 is. Since the plating metal concentration in the plating solution is not lowered, the volume of the auxiliary cathode 4 is preferably small.
The auxiliary cathode 4 is not particularly limited as long as it is a conductive material, but it is preferable to use the same material as the plating metal in consideration of reprocessing.
When the insulator 2 is an edge mask, the cross-sectional shape of the edge mask is not particularly limited, but a U-shape is preferable because it does not easily collide with the material to be plated.
The material of the insulator 2 can be, for example, PET (polyethylene terephthalate), polyimide, phenol resin, epoxy resin, or the like.
In the present invention, as long as the auxiliary cathode is disposed on the side opposite to the material to be plated with the insulator interposed therebetween, the shape of the insulator is not limited, and the positional relationship between the insulator and the auxiliary cathode is not limited.
Further, in the present invention, the phrase “the insulator is disposed“ facing ”the material to be plated includes all positions as long as it faces the material to be plated. For example, when the material to be plated is a strip in the form of a strip (plate), the insulator may face the plate surface, or the insulator may face the end (edge) of the plate. However, in terms of effectively preventing edge overcoat, when the material to be plated is in the form of a band (plate), the insulator faces the edge (edge) of the plate (as shown in FIGS. 2 and 3). Is preferred.

Next, an edge overcoat preventing apparatus according to a second embodiment of the present invention will be described with reference to a sectional view 3 similar to FIG. As shown in FIG. 3, the edge overcoat prevention device 6B according to the second embodiment is the same as the edge overcoat prevention device according to the first embodiment except that the shape of the insulator 2B is different. The same parts are denoted by the same reference numerals and omitted.
In FIG. 3, the insulator 2B has a plate shape, the auxiliary cathode 4 is in close contact with the back surface of the insulator 2B (the surface opposite to the surface facing the copper foil strip 20), and the outer periphery of the auxiliary cathode 4 is the insulator 2B. It is located inside the outer periphery. The surface of the insulator 2B is perpendicular to the width direction (and end surface) of the copper foil strip 20.

Also in the second embodiment, since the insulator is disposed between the auxiliary cathode and the material to be plated, not only the edge overcoat is prevented by the auxiliary cathode but also the plating film deposited on the auxiliary cathode grows. Thus, reaching (contacting) the material to be plated is prevented. And edge overcoat can be prevented by consuming a plating current with an auxiliary cathode.
Furthermore, also in the second embodiment, since the outer peripheral edge of the insulator projects outward from the outer peripheral edge of the auxiliary cathode, the growth direction D of the plating film deposited on the auxiliary cathode is away from the material to be plated. Head. Therefore, the contact between the plating film and the material to be plated is further prevented.

Next, the current control of the auxiliary cathode will be described. As will be described in detail in Examples described later, as a result of intensive studies by the present inventors, the occurrence of edge overcoat is greatly affected by the current density of the auxiliary cathode and the distance between the auxiliary cathode and the material to be plated. There was found. First, when the distance between the auxiliary cathode and the material to be plated is close, the edge overcoat suppressing effect is produced even if the current density of the auxiliary electrode is low. On the other hand, if the distance between the auxiliary cathode and the material to be plated is increased, the effect of the auxiliary electrode is reduced. Therefore, in order to suppress the edge overcoat, it is necessary to increase the current density of the auxiliary electrode. This is presumably because, when the distance between the auxiliary cathode and the material to be plated or the current of the auxiliary cathode changes, the current distribution between the material to be plated changes and affects the edge overcoat.
Conversely, if the current density of the auxiliary cathode and / or the distance between the auxiliary cathode and the material to be plated is adjusted according to the size and configuration of the plating apparatus, the plating conditions, etc., the edge overcoat can be reliably applied. It can be suppressed. That is, there is an appropriate auxiliary cathode current density that does not result in an edge overcoat if only the auxiliary cathode current or the distance is adjusted.

From the above, the edge overcoat apparatus of the present invention has a gap adjusting means for adjusting the gap between the auxiliary cathode and the material to be plated and / or a current adjusting means for adjusting the current of the auxiliary cathode. preferable.
For example, the distance adjusting means may be structured such that the auxiliary cathode is movably attached to a predetermined position on a support member (for example, a beam extending from the side wall of the plating tank). Examples of the movable attachment include a structure in which the auxiliary cathode is screwed in any one of a plurality of attachment holes arranged in the beam.
Examples of the current adjusting means for adjusting the current of the auxiliary cathode include a power source (rectifier) connected to the auxiliary cathode and a resistor between the power source and the auxiliary cathode.

Next, with reference to FIGS. 4-6, the wiring aspect of the main power supply for to-be-plated materials (copper foil strip 20) and the power supply for the auxiliary cathode 4 is demonstrated.
FIG. 4 is a wiring diagram when a common main power source 70 is used as the main power source for the material to be plated 20 and the power source for the auxiliary cathode 4. The cathode terminal (−) of the main power supply 7050 is connected to the energizing roll 30 (via the copper foil strip 20) and also to each auxiliary cathode 4. The anode terminal (+) of the main power supply 70 may be connected to the anode 10, the cathode terminal (-), and each power supply may be a rectifier.
In the case shown in FIG. 4, since the power source for the material to be plated and the auxiliary cathode is common, in order to effectively suppress the edge overcoat, a resistance is inserted between the auxiliary cathode and the power source to adjust the current of the auxiliary cathode. Alternatively, it is preferable to change the interval between the auxiliary cathode and the material to be plated.

FIG. 5 is a wiring diagram when the power source 80 for the auxiliary cathode 4 is used separately from the main power source 70 for the material to be plated 20. The cathode terminal (−) of the main power supply 70 is connected to the energizing roll 1 (through the copper foil strip 20), and the anode terminal (+) is connected to the anode 10.
On the other hand, the anode terminal (+) of the auxiliary cathode power source 80 is connected to the anode 10, and the cathode terminal (−) is connected to each auxiliary cathode 4 in parallel.
In the case of the wiring shown in FIG. 5, the material to be plated 20 and the auxiliary cathode 4 are controlled by separate power sources, so that the current adjustment of the auxiliary cathode is easy and the edge overcoat can be easily suppressed.

FIG. 6 is a wiring diagram when power sources 81 and 82 for the auxiliary cathode 4 are used separately from the main power source 70 for the material to be plated 20. The cathode terminal (−) of the main power supply 70 is connected to the energizing roll 1 (through the copper foil strip 20), and the anode terminal (+) is connected to the anode 10.
On the other hand, the anode terminal (+) of the auxiliary cathode power supply 81 is connected to the anode 10, and the cathode terminal (−) is connected to the left auxiliary cathode 4. The anode terminal (+) of the auxiliary cathode power source 82 is connected to the anode 10, and the cathode terminal (−) is connected to the right auxiliary cathode 4.

In the case of the wiring shown in FIG. 6, the material to be plated 20 and the auxiliary cathode 4 are controlled by separate power sources, so that the current adjustment of the auxiliary cathode is easy and the edge overcoat can be easily suppressed. In the case of the wiring shown in FIG. 6, since the left and right auxiliary cathodes 4 are connected to separate auxiliary cathode power supplies, the current (density) of the auxiliary cathodes at both ends can be changed. Therefore, it is possible to prevent the edge overcoat at one end from becoming noticeable due to meandering of the material to be plated.
In addition, if the current density of the auxiliary cathode whose distance to the plating material is narrow due to meandering is low and the current density of the auxiliary cathode whose distance is wide is high, the plating on both edges of the material to be plated The thickness can be made substantially equal (uniform), and edge overcoat does not occur or become noticeable at one end.

In the edge overcoat prevention device of the present invention, it is preferable that an anode mask is provided on the anode facing the material to be plated.
7 and 8 each show an example of the anode mask. In FIG. 7, the anode mask 11 covers both end portions of the anode 10, end edges of the facing surface of the anode 10 facing the material to be plated 20, and the back surface of the anode 10. In FIG. 8, the anode mask 11 </ b> B includes both end portions of the anode 10, positions where the anode 10 is slightly separated from the edge portion of the surface facing the material to be plated 20, and the back surface of the anode 10. And covering. That is, the anode mask 11 </ b> B has a protruding portion 11 x extending from both end portions of the anode 10 toward the material to be plated 20.
The anode mask suppresses an overcoat by suppressing a current leaking from the anode to the outside, and makes the amount of plating adhered in the width direction of the material to be plated uniform. The shape of the anode mask is not limited as long as it reduces the edge current that leaks from at least both ends of the anode to the outside (to-be-plated material side), and an insulating plate or the like can be used.

However, when copper foil or the like is plated on one side of a material previously laminated on one side with a resin film, the overcoat cannot be sufficiently suppressed even if an anode mask is used. Therefore, in the present invention, the current density applied to the auxiliary cathode can be reduced by using the auxiliary mask together with the auxiliary cathode instead of using the anode mask alone, and the plating metal can be further prevented from being deposited on the auxiliary cathode. .
For this purpose, in the present invention, when the current of the auxiliary cathode can be adjusted independently of the current applied to the material to be plated (for example, the auxiliary cathode is connected to a power source separate from the main power source, An anode mask is used when the current density of the cathode can be controlled independently.
For example, as described above, when the current density of the auxiliary cathode is made lower than the current density of the material to be plated, the effect of the auxiliary cathode does not occur unless the current density of the auxiliary cathode exceeds a certain threshold value. If the anode mask is used, an effect is obtained that the threshold value of the current density of the auxiliary cathode can be lowered.

In the method for producing an electroplating material of the present invention, an insulator is disposed so as to face the material to be plated, an auxiliary cathode is disposed on the opposite side of the material to be plated across the insulator, and the outside of the auxiliary cathode is disposed. The peripheral edge is positioned inside the outer peripheral edge of the insulator, and electroplating is performed on the material to be plated using the material to be plated and the auxiliary cathode as a cathode. The material and shape of the material to be plated, the insulator, and the auxiliary cathode, and the arrangement mode of the insulator and the auxiliary cathode can be the same as those in the edge overcoat prevention device described above.
The present invention is not limited to the above embodiment, and as long as the insulator is disposed to face the material to be plated, for example, the surface of the insulator may be disposed obliquely with respect to the end surface of the material to be plated. In short, it is only necessary to adjust the positions of the auxiliary cathode and the insulator so that the current flowing from the main electrode to the material to be plated is consumed by the auxiliary cathode.
Further, the auxiliary cathode and the insulator may be in close contact with each other or may be separated from each other.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

<Experiment 1>
Using a vertical continuous electroplating apparatus shown in FIG. 1, a PET film (12.5 μm) is laminated on one side of a rolled copper foil (7.8 μm) as a material to be plated (strip) with an adhesive layer having a thickness of 3 μm. (Width (W) 600 mm) was used, and plating was performed on one side (copper exposed surface) of the strip. Sn plating with a thickness of about 1 μm was performed at a plating line speed of 5 m / min, a current density of 10 A / dm ² , and a plating time of 15 s.
As the edge overcoat prevention device, the one shown in FIG. 3 was used. As the auxiliary cathode 4, Sn (99.9%) having a length of 1500 mm in the longitudinal direction (720 mm in the liquid surface), a width of 50 mm, and a thickness of 0.05 mm was used. The distance between the strip ends and the auxiliary cathode was 60 mm. The dimensions of the insulator 2B are as follows: d = 1200 mm in FIG. 9 (720 mm in the liquid surface), e = 50 mm, f = 55 mm, and g = 10 mm.
Moreover, in Experiment 1, the effect by the difference in the current density and distance of a to-be-plated material and an auxiliary cathode was calculated | required. Therefore, the power supply arrangement of FIG. 4 (common power supply) is used in Invention Example 1, and the power supply arrangement (power supply is separate) of FIG. 5 is used in Invention Example 2. In addition, in order to find out the threshold value of the current density of the auxiliary cathode, a reference example 1 was obtained in which the current density of the auxiliary cathode was lower than that of Invention Example 2.

<Evaluation>
1. Edge overcoat on the material to be plated The plating thickness at the center and both ends of the material to be plated was measured with a fluorescent X-ray film thickness meter SFT8000 (manufactured by SII). The portion 200 to 400 mm inside from the edge of the material to be plated was used as the center, and several plating thicknesses were measured at a measurement interval of 10 mm in the width direction, and the average value of the measurement group was determined as the plating thickness at the center.
Also, regarding the plating thickness at both ends of the material to be plated, the edge from 10mm to the inside is regarded as the edge, the measurement length is 1000mm or more, several points are measured at 100mm intervals in the length direction, and the average value of the measurement group is measured at both ends. It was set as the plating thickness of the part (edge part).
The edge overcoat was evaluated according to the following criteria. If the evaluation is Δ or ◯, there is no practical problem.
A: If the plating thickness at the center of the material to be plated is 1, the plating thickness at both ends is between 0.7 and 1.3.
(Triangle | delta): If the plating thickness of the center part of a to-be-plated material is 1, the plating thickness of both ends is 0.7 or less.
X: When the plating thickness at the center of the material to be plated is 1, the plating thickness at both ends is 1.3 or more.
In addition, when the plating thickness at both ends deviates from the above standard even at one end, evaluation based on the deviated value was performed. Therefore, if the film thickness is 1.3 or more at one end of the plating thicknesses at both ends, the evaluation is x.

2. Precipitation of plating metal (Sn) on the auxiliary cathode
After 24 hours of continuous plating, it was visually determined whether Sn precipitates extended from the auxiliary cathode toward the material to be plated (strip). Further, the auxiliary cathode was taken out and the amount of Sn deposited on the auxiliary cathode surface was measured. In the measurement, the thickness of the auxiliary electrode before the test was first measured with a micrometer at intervals of 10 mm in the width direction, and the thickness was similarly measured after the test. And Sn precipitation amount was converted from the difference in thickness before and after the test (Sn precipitation amount = Auxiliary electrode area × Plating thickness average value × Sn specific gravity).
The following comprehensive evaluation was performed from the results of the visual determination and the Sn precipitation amount.
A: No precipitation of Sn in the direction of the plated part, the smallest amount of Sn precipitation (0.21 g / min)
○: Sn does not precipitate in the direction of the plated part, Sn precipitation is small (1.11 g / min)
No precipitation of Sn in the direction of the plated part, large amount of Sn precipitation (1.38 g / min)
×: Sn is deposited in the direction of the plated part

<Experiment 2>
Experiments and evaluations were performed in the same manner as in Experiment 1 except that the apparatus shown in FIG. 2 was used instead of the apparatus shown in FIG.
The dimensions of the insulator 2 were set to a = 50 mm, b = 30 mm, c = 60 mm, and d = 1200 mm (720 mm in the liquid surface) in FIG. The distance between the auxiliary cathode and the strip end face was 60 mm.
Moreover, also in Experiment 1, the effect by the difference in the current density and distance of a to-be-plated material and an auxiliary cathode was calculated | required. Therefore, the power supply arrangement shown in FIG. 4 (common power supply) is used in Invention Example 3, and the power supply arrangement shown in FIG. 5 (power supply is separate) is used in Invention Example 4. Further, in order to find out the threshold value of the current density of the auxiliary cathode, a reference example 2 was obtained in which the current density of the auxiliary cathode was lower than that of Invention Example 4.

<Experiment 3>
Experiments and evaluations were performed in the same manner as Experiment 2 except that the anode mask shown in FIG. 8 was further used.
The dimensions of the anode mask 11B were p = 5 mm, q = 200 mm, and r = 600 mm in FIG. 8, and the length of the anode mask 11B in the paper surface direction in FIG. 8 was 850 mm.
Also in Experiment 3, the effect of the difference in current density and distance between the material to be plated and the auxiliary cathode was determined. For this reason, the power supply arrangement shown in FIG. 4 (common power supply) is used in Invention Example 5, and the power supply arrangement shown in FIG. Further, in order to find out the threshold value of the current density of the auxiliary cathode, a reference example 3 was obtained in which the current density of the auxiliary cathode was lower than that of Invention Example 7.

  The obtained results are shown in Table 1. In Table 1, “A” in Experiment 1A indicates a case where the distance between the material to be plated (strip) and the auxiliary cathode (distance closest to the material to be plated) is constant at 60 mm. In addition, the appendix “B” in Experiment 1B shows the case where the interval is changed. Experiments 2 and 3 are the same.

(Experiment 1A)
In the case of Experiment 1A in which the distance is 60 mm, even when the current density of the material to be plated and the auxiliary cathode is the same (Invention Example 1), the deposition of the plating metal on the edge overcoat and the auxiliary cathode is evaluated by Δ. There was no problem in practical use. In the case of Invention Example 2 in which the current density of the auxiliary cathode was made lower than the current density of the material to be plated, the plating metal deposition on the edge overcoat and the auxiliary cathode was both evaluated as ◯, and the current density was the same. The evaluation was superior to that of Example 1.
On the other hand, in the case of Reference Example 1 in which the current density of the auxiliary cathode was reduced to 6 A / dm ² , the evaluation of the edge overcoat deteriorated. This shows that the current density of the auxiliary cathode has a lower limit (7 A / dm ² ), and it is preferable to make the current density of the auxiliary cathode higher than the lower limit and lower than the current density of the material to be plated.

(Experiment 2A, 3A)
Similar results were obtained in Experiment 2A, and the lower limit of the current density of the auxiliary cathode in Experiment 2A was 7 A / dm ² (Invention Example 4).
Similar results were obtained in Experiment 3A, but the lower limit of the current density of the auxiliary cathode in Experiment 3A was 1.5 A / dm ² (Invention Example 7). When an anode mask was used, the lower limit of the current density of the auxiliary cathode was It has been found that the operating range of the current density of the auxiliary cathode is widened.

(Experiment 1B)
When the interval is increased from 60 mm, when the interval is 85 mm, the current density of the material to be plated and the auxiliary cathode is the same as in Experiment 1A (Invention Example 1), and there is no edge overcoat and auxiliary The deposition of the plating metal on the cathode was evaluated as Δ, and there was no practical problem. On the other hand, when the interval was increased to 260 mm, an edge overcoat occurred when the current density of the material to be plated and the auxiliary cathode was the same ( Reference Example 1). Therefore, when the current density of the auxiliary cathode was increased from the current density of the material to be plated (Invention Example 2), edge overcoat could be prevented.
From the above, it can be seen that edge overcoat can be reliably suppressed by adjusting the current density of the auxiliary cathode and / or the distance between the auxiliary cathode and the material to be plated.

(Experiment 2B, 3B)
In Experiment 2B, the same results as in Experiment 1B were obtained.
In Experiment 3B, even if the interval is increased, the current density of the material to be plated and the auxiliary cathode is made the same (Invention Example 5), or the current density of the auxiliary cathode is made lower than the current density of the material to be plated (Invention Example). 6, 7), edge overcoat could be suppressed.

<Experiment 4>
In the same manner as in Experiment 2A or Experiment 3A, the interval was set to 60 mm, and the experiment and evaluation were performed. However, in FIG. 2, the strip position was moved 40 mm to the left from the center, and the distance between the strip end face and the left auxiliary cathode was 20 mm. On the other hand, in the right edge overcoat prevention device, the distance between the auxiliary cathode and the strip end face was 20 mm.
In Experiment 4, in order to change the current density of the left and right auxiliary cathodes, the power supply arrangement shown in FIG. 6 (the auxiliary cathode power source was provided separately from the main power source, and separate auxiliary cathode power sources were provided for the left and right auxiliary cathodes, respectively. ). Further, in order to determine the effect of the anode mask, Example 7 was used without using the anode mask, and Example 8 was used with the anode mask of FIG.
On the other hand, reference examples 4 and 5 were obtained in which the current densities of the left and right auxiliary cathodes were the same. However, Reference Example 4 did not use an anode mask, and Reference Example 5 used an anode mask.
The obtained results are shown in Table 2.

As is clear from Table 2, in the case of Invention Examples 8 and 9, the current density of the left and right auxiliary cathodes is changed, the current density of the left auxiliary cathode, which is narrower from the material to be plated, is lowered, and the distance is increased. Since the current density of the auxiliary cathode on the right side is increased, the plating thicknesses at both edges of the material to be plated can be made substantially equal, and an edge overcoat occurs or becomes noticeable at one end of the material to be plated. It never happened.
In the case of Invention Example 9 using the anode mask, the current density of the auxiliary cathode could be made lower than that of Invention Example 8.
On the other hand, in Reference Examples 4 and 5 in which the current densities of the left and right auxiliary cathodes were the same, an edge overcoat occurred at the left end of the material to be plated, and the plating thickness was thinner at the right end than at the center. That is, the plating thicknesses at both edge portions of the material to be plated were significantly different.

Next, experiments and evaluations were performed on Comparative Examples not included in the present invention in the same manner as Experiments 1 to 3.
However, Comparative Examples 6 and 7 did not use an insulator in Invention Examples 1 and 2, respectively, and Comparative Example 8 did not use an insulator in Comparative Example 1. Comparative Examples 9 and 10 did not use an insulator in Invention Examples 5 and 6, respectively. In Comparative Example 11, plating was performed using the anode mask of FIG. 8 without using the edge overcoat prevention device of the present invention. In Comparative Example 12, plating was performed using only the edge mask of FIG. 2 and the anode mask of FIG. 8 without using the edge overcoat prevention device of the present invention. In Comparative Example 12, plating was performed using only the edge mask of FIG. 2 without using the edge overcoat prevention device of the present invention. In Comparative Examples 6 to 11, the distance between the material to be plated (strip) and the auxiliary cathode (the distance closest to the material to be plated) was constant at 60 mm.

  The obtained results are shown in Table 3.

As is apparent from Table 3, in Comparative Examples 6 to 10 using only the auxiliary cathode, Sn deposition was confirmed on the auxiliary cathode in the direction of the material to be plated. This indicates the possibility that the deposited Sn and the material to be plated collide.
In Comparative Examples 11 to 13 where no auxiliary cathode was used, edge overcoat could not be prevented.

It is a whole block diagram of the continuous electroplating apparatus by which an edge overcoat prevention apparatus is arrange | positioned. It is sectional drawing which shows the edge overcoat prevention apparatus which concerns on the 1st Embodiment of this invention when a copper foil strip is cut | disconnected by the surface parallel to the paper surface direction of FIG. It is sectional drawing which shows the edge overcoat prevention apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the power supply wiring to the edge overcoat prevention apparatus which concerns on embodiment of this invention. It is another figure which shows the power supply wiring to the edge overcoat prevention apparatus which concerns on embodiment of this invention. It is another figure which shows the power supply wiring to the edge overcoat prevention apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the anode mask in the edge overcoat prevention apparatus which concerns on embodiment of this invention. It is sectional drawing which shows another anode mask in the edge overcoat prevention apparatus which concerns on embodiment of this invention. It is a figure which shows the actual dimension of the edge overcoat prevention apparatus corresponding to FIG. It is a figure which shows the actual dimension of the edge overcoat prevention apparatus corresponding to FIG. It is sectional drawing which shows the electric lines of force at the time of using the conventional edge mask for single-sided plating.

Explanation of symbols

2 Insulator 4 Auxiliary cathode 6 Edge overcoat prevention device 10 Main electrode (anode)
20 Material to be plated (copper foil strip)
20c Edge of material to be plated

Claims (9)

Used when electroplating strips ,
Insulators respectively disposed opposite to both ends of the strip ;
An auxiliary cathode disposed in the vicinity of the strip across the insulator,
A portion of the insulator extends inward from the end of the strip to form an edge mask covering the end;
An edge overcoat prevention device in which an outer peripheral edge of the auxiliary cathode is positioned inside an outer peripheral edge of the insulator along a thickness direction of the strip . Edge overcoat protection device according to claim 1 one side Ru insulating der of the strip. The auxiliary cathode and the gap adjusting means for adjusting the distance between the strips, and / or the edge overcoat protection device according to claim 1 or 2 that have a current adjusting means for adjusting the current of the auxiliary cathode. 4. The edge overcoat prevention device according to claim 3 , wherein the current adjusting means is capable of adjusting the current of the auxiliary cathode independently of the current applied to the strip . The auxiliary cathode is disposed opposite the ends of the strip, said current adjusting means edge overcoat prevention device according to claim 3 or 4 Ru adjustable der the auxiliary cathode current independently. The edge overcoat prevention device according to claim 5, further comprising an anode mask on an anode facing the strip . The edge overcoat prevention device according to any one of claims 1 to 6, wherein the current density of the auxiliary cathode is set to 7 A / dm ² or more and lower than the current density of the strip.   The edge overcoat prevention apparatus in any one of Claims 1-7 which adjusts the space | interval of the said auxiliary cathode and the said strip to 85 mm or less. Insulators are respectively disposed opposite to both ends of the strip, and an edge mask is formed in which a part of the insulator extends inward from the end of the strip and covers the end,
An auxiliary cathode is disposed on the opposite side of the strip across the insulator, and the outer peripheral edge of the auxiliary cathode is positioned inside the outer peripheral edge of the insulator along the thickness direction of the strip ,
A method of manufacturing an electroplating material for electroplating the strip using the strip and the auxiliary cathode as a cathode.

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