JP2012057191A - Method for electroplating long conductive substrate, method for manufacturing copper-coated long conductive substrate using the method and roll-to-roll type electroplating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a copper-coated long conductive substrate, whereby surface accuracy of a copper plating layer on the copper-coated long conductive substrate can be improved.SOLUTION: The method for electroplating a long conductive substrate comprises: sending the long conductive substrate so that it is kept substantially horizontal in its width direction; and depositing a metal plating film layer on a surface of a seed layer by a wet plating method by an electroplating method using a plurality of insoluble anodes. The plurality of insoluble anodes are electrically divided into at least two portions in a sending direction. Among the divided insoluble anodes, those depositing an electroplating film with a total film thickness of ≤2 μm has a current density controlled to ≤2 mA/cm.

Description

  The present invention relates to a technique for producing a long conductive substrate such as a copper-coated polyimide substrate used for a flexible wiring substrate, and more specifically, a copper-coated long length having a high-quality plating film without a recess on the surface of the plating layer. The present invention relates to a method for producing a conductive substrate and a roll-to-roll type electroplating apparatus.

  As an example of a flexible wiring board, COF (Chip on Film) has attracted attention as a technique for mounting a driver IC chip for displaying a liquid crystal screen. This COF is capable of fine pitch mounting as compared with TCP (Tape Carrier Package), which is a conventional mounting method, and is an easy mounting method for reducing the size and cost of the driver IC chip.

  In general, for COF, for example, it is known to use a copper-coated polyimide substrate obtained by bonding a polyimide film, which is a high heat resistance and high insulating resin, and a metal layer, which is a conductor. This COF substrate is used for mounting by forming a fine wiring pattern on a metal layer of a copper-coated polyimide substrate by a subtractive method using a photolithography method, and further covering a desired portion with tin plating and a solder resist. Is.

  Here, in the case of producing a flexible wiring board by the subtractive method, first, a resist layer is provided on the metal layer surface of the copper-coated polyimide substrate, and a mask having a predetermined wiring pattern is provided on the resist layer. Then, exposure is performed by irradiating ultraviolet rays from above, and development is performed to obtain an etching mask for etching the metal layer, and then the exposed metal portion is removed by etching, and then the remaining resist layer is removed. It is prepared by washing with water and, if necessary, applying predetermined plating to the lead terminal portion of the wiring.

As a method for forming a metal layer on the surface of the polyimide film, there are a manufacturing method of a three-layer substrate in which a polyimide film and an electrolytic copper foil or the like are bonded with an adhesive, and a metalizing method.
Among these, the metalizing method first forms a metal layer such as a nickel-chromium alloy by a dry plating method, and subsequently forms a metal layer such as copper by a dry plating method in order to impart good conductivity. A stack of a metal layer such as a nickel-chromium alloy and a metal layer such as copper is referred to as a seed layer. Further, the thickness of the metal layer is increased by using an electroplating method on the surface of the seed layer or by using an electroless plating method and an electroplating method in combination, thereby forming a metal layer having a desired thickness. The copper-coated polyimide substrate produced by this metallizing method is less affected by the adhesive than the three-layer substrate, and it is possible to obtain a copper-coated polyimide substrate utilizing the original characteristics of polyimide including high-temperature stability. It has the advantage of being able to.

  When copper is selected for the metal layer formed on the surface of the seed layer, an electroplating method is usually used, and a soluble phosphorus-containing copper ball is used for the anode (see Patent Document 1). By dissolving the phosphorus-containing copper balls of the anode, copper ions are supplied into the plating solution. At that time, impurities in the phosphorus-containing copper balls diffuse into the plating solution as a residue called anode slime, and contaminate the plating solution. It is considered that these contaminants adhere to the plating substrate, thereby causing unevenness on the surface of the plating film, that is, generation of plating nodules due to the anode slime. If unevenness is present on the surface of the plating film, disconnection occurs during wiring processing or mounting, which causes a significant decrease in reliability.

On the other hand, as a plating method that does not generate anode slime in principle, a method using an insoluble anode has been proposed.
This insoluble anode has been used for a long time in the process of electrolytically collecting excess metals and impurities in metal smelting and the like (see Patent Document 2).

  In recent years, this method using insoluble anodes has been used to solve problems caused by anode slime in the electroplating process. As an alternative to soluble metal anodes, it is insoluble in the anode chamber separated from the plating solution by an ion exchange membrane. When a conductive anode is placed and copper plating treatment is performed, a dedicated tank filled with copper oxide is installed as a copper ion supply source, and the plating solution and the plating solution in this bath are circulated in the plating solution. A plating method for controlling the copper ion concentration is proposed (see Patent Document 3).

Japanese Patent Laid-Open No. 2000-256891 Japanese Patent Laid-Open No. 10-60678 JP 2004-269955 A

  However, in the above-described conventional technology, the copper electroplating method using the insoluble anode is the disconnection at the time of wiring processing or mounting due to the generation of the anode slime in the copper electroplating method using the conventional soluble anode. Although it greatly contributes to suppression, defects such as protrusions and dents on the surface of the copper plating layer, which are required by the recent progress of fine pitch wiring and expanded applications such as copper-coated polyimide substrates, are possible. It cannot be said that it is sufficient as a method of reducing as much as possible.

  In view of such a situation, the present invention can manufacture a high-quality copper-coated polyimide substrate that can extremely reduce the dents on the surface of the metal plating layer and further suppress disconnection during wiring processing or mounting of the substrate. The present invention intends to propose a method for electroplating a long conductive substrate, a method for producing a copper-coated long conductive substrate using this method, and a roll-to-roll type electroplating apparatus.

  In order to solve such problems, the present inventors have intensively studied a method for producing a long conductive substrate such as a copper-coated polyimide substrate having few defects on the surface of the copper plating layer. Is divided into two or more electrically in the transport direction, and the current density is controlled independently for each insoluble anode, and the current value applied to each insoluble anode is changed. As a result, it was found that the dents on the surface of the copper plating layer can be greatly reduced, and the present invention has been found.

That is, in the electroplating method for a long conductive substrate according to the present invention, the long conductive substrate is transported so that the width direction is substantially horizontal, and a plurality of insoluble anodes are used on the surface of the seed layer. In the electroplating method for a long conductive substrate in which a metal plating film layer is formed by a wet plating method using an electroplating method, the plurality of insoluble anodes are electrically divided into at least two in the transport direction. In addition, among the divided insoluble anodes, the current density of the insoluble anode for forming a film having a total electroplating film thickness of 2 μm or less is controlled to ² mA / cm ² or less. is there.

  In addition, the method for producing a copper-coated long conductive substrate according to the present invention uses the method of electroplating a long conductive substrate according to the present invention, and the long conductive substrate is at least one surface of a long resin film. It is a long resin film with a seed layer in which a conductive seed layer is formed by dry plating without using an adhesive, and the metal plating film of the wet plating method by electroplating is a copper plating film It is characterized by.

Furthermore, the roll-to-roll type electroplating apparatus according to the present invention transports a long conductive substrate so that the width direction is substantially horizontal, and a plurality of insoluble anodes arranged in the transport direction. In the roll-to-roll type electroplating apparatus in which a metal plating film layer is formed on the surface of the seed layer by a wet plating method using an electroplating method, the insoluble anode is installed at the bottom of the electrolytic cell. An insoluble anode installed so as to face the substrate conveyed so as to descend and ascend in the cell via the conveyance guide roller, and is electrically divided into two or more in the same conveyance direction, and The divided lowermost insoluble anode is disposed so that the curved portion formed at the lower end thereof faces the conveying guide roll in the plating solution tank, and the divided insoluble anode is further separated. And it is characterized in that it forms a mechanism that the current density is controlled independently for each disintegrable anode.
The plurality of insoluble anodes may be a metal anode using platinum or lead, or a titanium frame coated with a ceramic film having at least one conductivity selected from iridium oxide, rhodium oxide, and ruthenium oxide by firing. It is preferable that the ceramic-based anode be a modified embodiment. The plurality of insoluble anodes are in a preferred form even if they are mesh-shaped or provided with a cation exchange membrane.

  According to the present invention, productivity of electroplating on a long conductive substrate can be improved, and a high-quality electroplating film with extremely few defects due to a dent having a diameter of 5 μm or more can be formed on the surface of the electroplating layer. It becomes possible. Moreover, it is possible to obtain a copper-coated polyimide substrate having high processing accuracy and useful for fine pitch. More specifically, the copper-coated polyimide substrate obtained by the present invention can increase the processing accuracy by greatly reducing the dents on the surface of the copper plating layer that cause disconnection during wiring processing. Specifically, the number of recesses having a diameter of 20 μm or less can be suppressed to a quarter or less, which is suitable for a fine pitch COF having a pitch of 30 μm or less, and has an extremely large industrial value.

It is a flowchart which shows the general manufacturing process of the copper covering polyimide board shown as one Example of a copper covering long electroconductive board | substrate. It is sectional drawing of the copper covering polyimide substrate by this invention. 1 is a schematic side view showing an embodiment of a roll-to-roll type electroplating apparatus according to the present invention. It is a schematic side view which expands and shows a part of electroplating cell of the electroplating apparatus shown in FIG. It is a schematic front view which expands and shows a part of insoluble anode of the electroplating cell of the electroplating apparatus shown in FIG. 3 and FIG. It is a schematic side view which expands and shows a part of anode electroplating cell provided with the diaphragm with the electroplating apparatus shown in FIG.

The roll-to-roll type plating apparatus and the method for plating a long conductive substrate according to the present invention will be described by taking a method for producing a copper-coated polyimide substrate as an example.
As shown in FIG. 1, the copper-coated polyimide substrate is manufactured by performing a sputtering process and an electroplating process on a raw material polyimide film to form a desired metal film. The copper-coated polyimide substrate manufactured by this method does not require an adhesive, so it can utilize the original characteristics of polyimide such as high heat resistance and high insulation, and can be bent and used during mounting. Therefore, it can greatly contribute to miniaturization of the device.

(1) Copper-coated polyimide substrate:
The copper-coated polyimide substrate according to the present invention is formed by laminating a base metal layer 3 such as a nickel-chromium alloy, a copper thin film layer 4 and a copper plating film layer 5 on the surface of the polyimide film 2 as shown in FIG. A laminated body of the base metal layer 3 and the copper thin film layer 4 is referred to as a seed layer 6. The copper plating film layer 5 may be formed in combination with the electroless plating method.

  As a method for producing a copper-coated polyimide substrate according to the present invention, first, a base metal layer 3 such as nickel, a nickel-based alloy or chromium is formed on the surface of the polyimide film 2 by a sputtering method. The thickness of the base metal layer 3 is not particularly limited, but is generally 5 to 50 nm. Known nickel alloys such as nickel-chromium alloy, nickel-chromium-molybdenum alloy, nickel-vanadium-molybdenum alloy can be used as the nickel-based alloy that can be used for the base metal layer. However, the metal used for the base metal layer needs to pay attention to the insulating property of the flexible wiring board and the etching property by the subtractive method. Subsequently, in order to give good conductivity to the surface of the base metal layer 3, the copper thin film layer 4 is subsequently formed by a sputtering method of a dry plating method. The thickness of the copper thin film layer 4 formed by this process is generally 50 to 500 nm.

Further, a copper layer made of the copper plating film layer 5 is provided on the surface of the seed layer 6 made of a laminate of the base metal layer 3 and the copper thin film layer 4, that is, on the surface of the copper thin film layer 4. The copper layer formed of the copper plating film layer 5 has a desired film thickness by an electroplating method which is a kind of wet plating method or a combination of an electroless plating method and an electroplating method which are a kind of wet plating method. The film thickness of the copper layer 5 formed on the surface of the seed layer is generally 5 to 18 μm, for example, when a circuit pattern is formed by a subtractive method.
When the copper layer 5 is formed by using both electroless plating and electroplating, copper is formed on the surface of the seed layer 6 by electroless plating, and then the surface of the film formed by electroless plating is used. Electroplating.

(2) Electroplating equipment:
As shown in FIG. 3, a roll-to-roll type electroplating apparatus for carrying out the method of the present invention comprises a plating solution tank 11, an unwinding roll 12, a transporting guide roll 13, an insoluble anode (hereinafter referred to as “insoluble anode”). 14a to 14h), a winding roll 15, and power feeding rolls 16a to 16e. Note that F is a long polyimide film with a seed layer, and S is a copper-coated long polyimide film (copper-coated polyimide substrate).

  Here, the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h each constitute an electrically independent electroplating cell. Therefore, the surface of the metal film (for example, a copper thin film layer) of the long polyimide film F with the seed layer is in contact with the power supply rolls 16a, 16b, 16c, 16d, and 16e, so that the anodes 14a, 14b, 14c, 14d, A potential difference is generated between 14e, 14f, 14g, and 14h, and electroplating is performed.

  The anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h are connected to positive electrodes of control power sources (also referred to as rectifiers, not shown) that are electrically independent of each other. The negative electrode of this control power source is connected to the power supply rolls 16a, 16b, 16c, 16d, and 16e. That is, the anode 14a constitutes an electroplating circuit by the control power source connected to the anode 14a, the feed roll 16a, and the long polyimide film F with a seed layer. Similarly, the anodes 14b, 14c, 14d, 14e, 14f, 14g, and 14h constitute an electroplating circuit.

Furthermore, the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h are controlled in current density by a control power source connected to each anode so that the current density increases stepwise from the unwinding roll 12 side. Has been made. The control for increasing the current density in stages is appropriately determined in consideration of the film thickness of the copper plating film layer.
In addition, the electroplating apparatus includes various known apparatuses used for transporting a long polyimide (resin) film such as a control roll for controlling the tension of the long polyimide film F with a seed layer, and stirring and supply of a plating solution. Various known devices can also be added.

  In the electroplating apparatus 1 shown in FIG. 3, the plating solution tank 11 is filled with an acidic plating solution mainly composed of sulfuric acid and copper sulfate. The long polyimide film F with the seed layer is unwound and conveyed from the unwinding roll 12 with the width direction being substantially horizontal, and the conveying direction is changed so as to be immersed in the plating solution in the plating solution tank 11 by the power supply roll 16a. Inverted by the conveying guide roll 13 in the plating solution tank 11, the conveying direction can be changed in the plating solution surface direction of the plating solution tank 11. Further, the adjacent power feed roll 16b, transport guide roll 13, power feed roll 16c, transport guide roll 13, power feed roll 16d, transport guide roll 13, and power feed roll 16e are transported in this order to immerse in the plating solution. Repeated. Finally, the copper-coated long polyimide film S (in this state, since electroplating is completed, it becomes a copper-coated polyimide substrate) is wound up by the winding roll 15.

  In the electroplating apparatus 1 shown in FIG. 3, the long polyimide film F with a seed layer is immersed in a plating solution vertically. The direction in which the long polyimide film F with the seed layer is immersed is not limited to vertical, but may be immersed obliquely into the plating solution in the plating solution tank 11. The direction in which the long polyimide film with a seed layer (long conductive substrate) F is immersed in the plating bath 11 can be appropriately selected.

(3) Anode:
As an example, the anode constituting the electroplating cell of the electroplating apparatus of the present invention has an enlarged anode 14g and anode 14h, as shown in FIG. The upper anodes 14g-1, 14h-1, and the lower anodes 14g-2, 14h-2 are divided into two in the conveyance direction of the polyimide film F, respectively. That is, in FIG. 4, the anode 14g is divided into an upper anode 14g-1 and a lower anode 14g-2, and the anode 14h is divided into an upper anode 14h-1 and a lower anode 14h-2, and the upper anodes 14g-1, 14h- Reference numeral 1 denotes a portion formed only from a flat portion, and the lower anodes 14g-2 and 14h-2 are formed from portions formed from curved portions. The upper ends of the upper anodes 14g-1 and 14h-1 are below the plating solution surface 11b, and the entire anodes 14g and 14h are immersed in the plating solution. Further, the lower anodes 14g-2 and 14h-2 are disposed so as to face the rolls so as to follow the conveyance guide rolls 13, respectively.
Here, the anode constituting the electroplating cell of the electroplating apparatus is formed so that the side section is substantially J-shaped, and the lower curved portion thereof is opposed to the roll so as to follow the conveying guide roll 13. The reason for this is that productivity can be improved by enabling electroplating to the long polyimide film F with a seed layer that is in contact with the transport guide roll 13. In the conventional roll-to-roll type electroplating apparatus, since the anode is composed only of a flat portion, the long polyimide film F with the seed layer that is reversed by the conveying guide roll 13 is plated. I couldn't.

As an example, the anodes 14g and 14h have a structure in which the anode 14g is attached as shown in FIG. 5, and the upper anode 14g-1 and the lower anode 14g-2 are electrically divided in the carrying direction into a frame 21g having electrical insulation. The upper anode 14g-1 is electrically connected to the bus bar 24g-1, and the lower anode 14g-2 is electrically connected to the bus bar 24g-2. Since the bus bar 24g-2 passes through the back surface of the frame 21g, it does not come into contact with the upper anode 14g-1. The bus bars 24g-1 and 24g-2 are placed on the edge of the plating bath, and the anode 14g is disposed through the frame 21g. Therefore, the anode 14g can be attached to and detached from the electroplating apparatus 1 freely. ing. The bus bars 24g-1 and 24g-2 are connected to independent control power sources.
Note that electrically dividing means that there is no electrical connection between the divided anodes. The anode 14g in FIG. 5 will be described as an example. The upper anode 14g-1 and the lower anode 14g-2 are arranged on the frame 21g having electrical insulation so that there is no electrical contact. That is, in the electroplating cell of the electroplating apparatus 1 of FIG. 3, all the anodes are electrically divided vertically in the plating solution depth direction.

In this way, the anodes are electrically divided in the conveying direction by connecting individual control circuits to the divided anodes, and controlling the current for each divided anode to obtain an arbitrary current density distribution. This is because it can be obtained, and the plating growth can be controlled in more detail.
The material of the frame 21g may be selected from materials that can maintain electrical insulation even in the plating solution and is not eroded by the plating solution, and a known plastic or ceramic having electrical insulation may be used.

In the present invention, the reason why the current density of the anode for forming a film having a total electroplating film thickness of 2 μm or less, that is, the lower anode, is limited to ² mA / cm ² or less is as follows.
When the current density of the lower anode exceeds ² mA / cm ² , the deposition rate of the electroplating film on the lower anode is increased, and foreign matter deposited on the bottom of the plating tank 11 is taken into the electroplating film, and the electroplating film Cause the formation of recesses. The long polyimide film F with the seed layer is electroplated to obtain a desired plating layer thickness. In the process of achieving the desired film thickness, the current density of the lower anode of the anode for electroplating the long polyimide film F with the seed layer having a total film thickness of 2 μm or less is set to ² mA / cm ² or less. . On the other hand, when the total film thickness of the electroplating film exceeds 2 μm, the current density of the lower anode may not be suppressed to ² mA / cm ² or less. The reason is that when the total thickness of the electroplating film exceeds 2 μm, even if the foreign matter deposited on the bottom of the plating tank 11 is taken into the electroplating film, it can be broken during wiring processing and mounting. This is because the generation of the dent having the property is greatly suppressed.

  In FIGS. 4 and 5, the anode is divided into two parts in the vertical direction. However, the division of the anode is not limited to two, and it may be divided into two or more. . Further, the lower anode may be formed only by a substantially J-shaped curved portion. If the anode is divided into a flat portion only and an anode including a curved portion, the position of the anode and the number of divisions are appropriately selected.

  Suitable materials for the anode include metal anodes such as platinum and lead, and ceramic-based anodes in which a titanium frame is baked and coated with conductive ceramics such as iridium oxide, rhodium oxide, or ruthenium oxide. Can be used. Preferably, a ceramic-based anode in which a titanium frame is coated with iridium oxide and rhodium oxide is employed. Since this anode uses ceramics, it is relatively stable even in a copper sulfate plating solution, and has the advantage that it can be regenerated by firing again when it deteriorates.

As the anode, a mesh ceramic anode can be used. This is because the formation of the mesh can more effectively prevent foreign matter and the like from being deposited on the curved portion of the substantially J-shaped anode.
Furthermore, as shown in FIG. 6, diaphragms 34g and 34h made of a cation exchange membrane may be provided so as to cover the anodes 14g and 14h. The cation exchange membrane is preferably a hydrocarbon or perfluorocarbon.

(4) Long conductive substrate:
As the long conductive substrate in the present invention, in addition to the long polyimide film with a seed layer, a metal strip such as a long copper foil, a long conductive polymer film, or the like can be used.
For example, the surface of an electrolytic copper foil or a rolled copper foil may be subjected to an electrochemical surface treatment. The thickness of these copper foils can be selected as appropriate, and electrolytic copper foils having a thickness of 5 μm to 15 μm are also known. The surface treatment includes a roughening treatment for forming a copper particle layer by electroplating of copper and a rust prevention treatment by electroplating such as a chromium alloy or a zinc alloy. In the roughening treatment by electroplating of copper, it is desirable that the surface be uniformly roughened, and it is not desirable that a recess having a diameter of 5 μm or more is generated. Similarly, dents are not desirable in the rust prevention treatment. In addition, the copper foil which performed such surface treatment is used for the current collection member of the three-layer copper covering polyimide substrate using an adhesive agent, or a secondary battery.
When a resin film with a metal thin film is used for the long conductive substrate, nickel, a nickel-based alloy, chromium, or the like can be selected as appropriate for the metal thin film. Examples of the resin film include resin films selected from polyimide films, polyamide films, polyester films, polytetrafluoroethylene films, polyphenylene sulfide films, polyethylene naphthalate films, and liquid crystal polymer films. In particular, a polyimide film and a polyamide film are desirable in that they are suitable for applications requiring high-temperature connection such as solder reflow. More preferably, it is a polyimide film. Moreover, the thing of 8-75 micrometers can use the thickness of an insulator film suitably. An inorganic material such as glass fiber can be appropriately added.
So far, the present invention has been carried out using a long polyimide film with a seed layer for a long conductive substrate. It goes without saying that the long conductive substrate is not limited to a long polyimide film with a seed layer.

  Examples will be described below.

  Using a Kapton 150EN (thickness: 38 μm) manufactured by Toray DuPont with a width of 50 cm for a long polyimide film, the polyimide film was kept at 150 ° C. for 1 minute in a chamber maintained at a vacuum degree of 0.01 to 0.1 Pa. The heat treatment was performed. Subsequently, a 7 nm thick nickel-chromium alloy layer containing 7% by weight of chromium was formed on this polyimide film by sputtering, and a copper layer was further formed to a thickness of 100 nm to obtain a long polyimide film F with a seed layer. For sputtering, a roll-to-roll type sputtering apparatus was used.

After sputtering, a copper layer having a thickness of 8 μm was formed by electroplating using the electroplating apparatus 1 shown in FIG. The basic composition of this plating solution is a copper sulfate solution having a pH of 1 or less, and a predetermined amount of an organic additive was added thereto for the purpose of ensuring the smoothness of the copper plating film.
The anode used in the electroplating process is divided, and the material is an iridium oxide anode.
Each anode was covered with a diaphragm made of a cation exchange membrane. Perfluorocarbon was used for the cation exchange membrane. For example, the anodes 14g and 14h include the diaphragms 34g and 34h as shown in FIG.

  A current density was applied to the anode as shown in Table 1. In this state, a copper-coated polyimide substrate was prepared, and defects on the surface of the copper plating layer were evaluated. Table 1 shows the state of current application to each anode.

  The surface defect is evaluated by performing an inspection of unevenness within a range of 470 mm in width and 50 mm in length using an unevenness detecting apparatus that optically detects unevenness, and corresponds to a size of 5 μm to 20 μm of the detected unevenness. Table 2 shows the number of objects per 50 mm × 50 mm.

  A current density was applied to the anode as shown in Table 1. In electroplating up to the anodes 14a, 14b, 14c, and 14d, the total thickness of electroplating does not exceed 2 μm. A copper-coated polyimide substrate was prepared, and defects on the surface of the copper plating layer were evaluated. Table 1 shows the state of current application to each anode. In addition, Table 2 shows the inspection results of the dents.

[Comparative Example 1]
A current density was applied to the anode as shown in Table 1. In this state, a copper-coated polyimide substrate was prepared, and defects on the surface of the copper plating layer were evaluated. Table 1 shows the state of current application to each anode. In addition, Table 2 shows the inspection results of the dents.

[Comparative Example 2]
A current density was applied to the anode as shown in Table 1. In this state, a copper-coated polyimide substrate was prepared, and defects on the surface of the copper plating layer were evaluated. In electroplating up to the anodes 14a, 14b, 14c, and 14d, the total thickness of electroplating does not exceed 2 μm. Table 1 shows the state of current application to each anode. In addition, Table 2 shows the inspection results of the dents.

  The surface of the electrolytic copper foil was further subjected to copper plating in the same manner as in Example 2 except that a 12 μm thick electrolytic copper foil was used instead of the long polyimide film with a seed layer, and defects on the surface of the copper plating layer were evaluated. . Table 3 shows the inspection results of the dents.

[Comparative Example 3]
The surface of the electrolytic copper foil was further subjected to copper plating in the same manner as in Comparative Example 2 except that an electrolytic copper foil having a thickness of 12 μm was used instead of the long polyimide film with a seed layer, and defects on the surface of the copper plating layer were evaluated. . Table 3 shows the inspection results of the dents.

  In Examples 1, 2, and 3 which implemented the manufacturing method of this invention, it turns out that the number of the dents on the surface of a copper plating layer is 1/4 or less compared with Comparative Examples 1, 2, and 3.

DESCRIPTION OF SYMBOLS 1 Electroplating apparatus 2 Polyimide film 3 Base metal layer 4 Copper thin film layer 5 Copper plating film layer 6 Seed layer 11 Plating solution tank 11b Plating solution surface 12 Unwinding roll 13 Guide rolls 14a-14h for conveyance Anode (insoluble anode)
14g-1, 14h-1 Upper anode 14g-2, 14h-2 Lower anode 15 Winding rolls 16a-16e Feed roll F Long polyimide film with seed layer 21g, 21h Frame 24g-1, 24g-2 Busbar 34g, 34h diaphragm

Claims (7)

A long conductive substrate is conveyed so that the width direction is substantially horizontal, and a metal plating film layer is formed on the surface of the seed layer by a wet plating method by an electroplating method using a plurality of insoluble anodes. In the electroplating method for a long conductive substrate, the plurality of insoluble anodes are electrically divided into at least two or more in the transport direction, and among the divided insoluble anodes, the total electroplating is performed. A method for electroplating a long conductive substrate, wherein the current density of an insoluble anode for forming a film having a thickness of 2 μm or less is controlled to ² mA / cm ² or less.   Use of the method for electroplating a long conductive substrate according to claim 1, and the conductive substrate is formed by a dry plating method in which the long conductive substrate is not provided with an adhesive on at least one surface of the long resin film. A method for producing a copper-coated long conductive substrate, characterized in that a long resin film with a seed layer on which a film is formed and a metal plating film of a wet plating method by electroplating is a copper plating film.   The seed layer is a laminate of a base metal layer selected from nickel, chromium or a nickel-based alloy provided on the surface of the long resin film and a copper thin film layer provided on the surface of the base metal layer. The manufacturing method of the copper covering long electroconductive board | substrate of Claim 2 characterized by the above-mentioned.   A long conductive substrate is transported so that the width direction is substantially horizontal, and a metal plating film is formed on the surface of the seed layer by a wet plating method using an electroplating method by a plurality of insoluble anodes arranged in the transport direction. In a roll-to-roll type electroplating apparatus for forming a layer, the insoluble anode is conveyed so as to descend and rise in the cell via a conveyance guide roller installed at the bottom of the electrolytic cell. The insoluble anode placed so as to face each of the substrates is electrically divided into two or more in the same transport direction, and the divided lowermost insoluble anode is formed at the lower end thereof The parts are arranged to face each other along the conveyance guide roll in the plating bath, and the current density is controlled independently for each of the divided insoluble anodes. Roll-to-roll type electroplating apparatus according to the present invention to symptoms.   The insoluble anode is a metal anode using platinum or lead, or a ceramic anode in which a titanium frame is coated with a ceramic film having at least one conductivity selected from iridium oxide, rhodium oxide, and ruthenium oxide by firing. The roll-to-roll type electroplating apparatus according to claim 4, wherein:   The roll-to-roll type electroplating apparatus according to claim 4, wherein the insoluble anode is in a mesh shape.   The roll-to-roll type electroplating apparatus according to any one of claims 4 to 6, wherein the insoluble anode is provided with a diaphragm made of a cation exchange membrane.

Images