JP5858286B2 - Method for electrolytic plating long conductive substrate and method for producing copper clad laminate - Google Patents

Description

  The present invention conveys a long conductive substrate using a roll-to-roll system, fills an electrolytic plating solution with an anode, and repeatedly immerses in an electrolytic plating tank to apply electrolytic plating to the surface of the long conductive substrate. The present invention relates to a method for electrolytic plating of a conductive substrate. Furthermore, it is related with the manufacturing method of the copper clad laminated board used for the electronic material using the electrolytic plating method of the elongate conductive substrate.

Electroplating is an industry that includes semiconductor circuit formation, surface treatment of steel strip and copper foil, production of electrolytic copper foil, and production of copper-clad laminates with a copper electrolytic plating film formed on the surface of a resin film such as polyimide. Widely used in the world.
The copper-clad laminate is processed into a flexible wiring board, and is used for COF (Chip on Film) mounting of driver circuits such as liquid crystal displays as well as small electronic devices such as mobile phones.
The flexible wiring board used in COF mounting was mainly 40-50 μm in wiring pitch (distance between the centers of adjacent wirings) before 2005, but in recent years, the wiring pitch has become 30 μm or less in fine wiring processing. ing.

  By the way, this flexible wiring board is manufactured by using a subtractive method or the like from a three-layer copper-clad laminate in which an adhesive is used between a polyimide film, which is a kind of resin film, and a copper foil. Is done.

  In recent years, as electronic components have become lighter, thinner, and smaller, the demand for narrower wiring has increased, so the demand for copper-clad laminates used has been increasing due to the demand for substrates that can draw fine wiring. Two-layer copper clad laminates without layers have been required. The reason is that by omitting the adhesive layer, a material using the inherent stability of the polyimide can be obtained without being affected by the properties of the adhesive layer.

As a method for obtaining the two-layer copper-clad laminate, Patent Document 1 discloses that a metal layer is directly laminated on the surface of a polyimide film by sputtering and vapor deposition, and then the thickness of the metal layer is increased by electrolytic plating or electroless plating. A so-called metalizing method has been proposed.
Patent Document 1 and its peripheral technology will be described. As a method of forming a metal layer on the polyimide film surface of a resin film when manufacturing a two-layer copper-clad laminate, first, for example, nickel, chromium, A base metal layer made of a nickel-chromium alloy or the like is formed, and a copper thin film layer is formed on the base metal layer to give good conductivity, thereby obtaining a metal thin film. Furthermore, in order to increase the thickness of the conductive layer for circuit formation, a copper plating film layer is usually formed by using an electroplating method or a combination of electroplating and electroless plating. The plate is used for COF mounting.

  In general, when a metal conductor is formed by an electrolytic plating method, an electrolytic plating bath is provided which is supplied with an electrolytic plating solution and has an anode disposed so as to face the electrolytic plating surface serving as a cathode inside the electrolytic plating bath. A plurality of tanks, which are two tanks, are installed side by side in the transport direction of the film-like substrate that is the material to be plated, and have a power feeding unit that supplies power to each electrolytic plating tank and a mechanism for continuously transporting the film-like substrate. A technique using the continuous plating apparatus is disclosed in Patent Document 2.

  In addition, a plurality of electrolytic plating tanks having an anode and an electrolytic solution are arranged, and an insulator film having a metal film having a thickness of 3 μm or less is successively supplied to these electrolytic plating tanks, and the amount of current applied to each electrolytic plating tank. There is known a continuous plating method in which the amount of energization in each electrolytic plating tank is sequentially increased according to the order in which the insulator films are supplied, and a uniform and favorable electrolytic plating film is continuously formed.

  Furthermore, when a copper-clad laminate is processed into a flexible wiring board, a long copper-clad laminated board is required because the wiring process is performed in a roll-to-roll manner. The long conductive substrate used for manufacturing is usually a coiled long substrate, but there are tip and terminal portions, and effective terminal processing in the electroplating method at these parts The method is not disclosed.

JP 2002-252257 A JP 2009-026990 A

Usually, the copper plating film layer formed by electrolytic plating of copper, which is the surface layer of a copper-clad laminate, requires smooth surface properties, but copper electrolysis of a two-layer copper-clad laminate using a metalizing method On the surface of the copper plating film layer, which is a plating layer, the concentration of minute protrusions may occur, and it has been found that the occurrence of the minute protrusions is caused by the electrolytic plating method.
Accordingly, the present invention provides an electrolytic plating method for a long conductive substrate that forms a smooth copper plating film layer without concentration of minute protrusions, and also uses a copper-clad coating that uses this long conductive substrate electrolytic plating method. The manufacturing method of a laminated board is provided.

  In order to solve the above-mentioned problems, the present inventor has intensively studied a method for producing a copper clad laminate board having a metal layer having no concentration of minute protrusions. As a result, energization is started in the plating process, after the immersion process in the plating bath. It was confirmed that the timing affects the surface defects of the obtained copper film, and the present invention has been achieved.

That is, the first invention of the present invention for solving the above-mentioned problem is that a long conductive substrate having a conductive surface is conveyed by a roll-to-roll method, and along the conveyance path of the long conductive substrate. A plurality of anodes are repeatedly immersed in an electrolytic plating solution filled in an electrolytic plating tank provided at a position facing the long conductive substrate, and the surface of the conductive layer of the long conductive substrate is subjected to electrolytic plating. In the method of electrolytic plating of a long conductive substrate, the long conductive substrate is provided with a long insulating substrate via a connecting portion at the tip end on the transport direction side, and the leading long insulating substrate leads to the electrolytic plating tank. After the leading long insulating substrate and the connecting portion are immersed in the electrolytic plating solution, the conductive layer tip of the long conductive substrate is immersed in the electrolytic plating solution. during the movement distance of 2% of a length up to 10% And it is characterized in that to start the energization of the anode to the opposite.

According to a second aspect of the present invention, the electroplating step on the surface of the conductive layer by immersing the long conductive substrate in the first invention in an electrolytic plating solution and energizing the opposing anode is performed on the long conductive substrate. When a plurality of anodes facing the long conductive substrate provided along the transport path are performed for each of the plurality of anodes, and when the conductive layer tip of the long conductive substrate is immersed in the electrolytic plating solution In the method of electroplating a long conductive substrate, the energization of the opposing anode is started while the tip of the conductive layer moves a distance of 2% to 10% of the length of the opposing anode. is there.

  According to a third aspect of the present invention, there is provided an electrolytic plating method for a long conductive substrate, wherein the electrolytic plating solution in the first and second inventions is a copper plating solution.

  According to a fourth aspect of the present invention, the long conductive substrate according to the first to third aspects comprises a base metal layer made of a nickel alloy thin film on the surface of the long resin film without an adhesive, and a copper thin film layer. It is the long electroconductive plating method of the elongate electroconductive board | substrate characterized by being the elongate resin film with a metal thin film laminated | stacked in order.

  5th invention of this invention is a manufacturing method of the copper clad laminated board which provided the electroplating film layer by the electroplating method of the elongate conductive substrate of 4th invention of this invention on the elongate conductive substrate surface. .

  According to the method of electrolytic plating of a long conductive substrate of the present invention, it becomes possible to obtain a copper-clad laminate substrate having a metal layer free from fine surface defects due to minute convex concentration portions on the surface of the copper electrolytic plating layer. , COF is suitable for COF mounting that can handle fine wiring processing.

It is a schematic diagram which shows an example of the electroplating apparatus of the roll-to-roll system for enforcing the electroplating method of this invention. FIG. 5 is a schematic cross-sectional view showing a connection portion between a long conductive substrate and a long insulating substrate, where (a) shows a case where the long insulating substrate overlaps the power supply roll contact surface side of the long conductive substrate; (b) is a figure which shows the case where a long insulating board | substrate has overlapped on the base-material side surface of a long conductive board | substrate. FIG. 6A is a diagram illustrating the timing of energization, in which FIG. 10A is a diagram illustrating when a conductive layer tip of a long conductive substrate is immersed in an electrolytic plating solution, and FIG. 10B is 10% of the anode length of the anode facing the conductive layer tip. It is a figure which shows the time of moving the distance to. It is sectional drawing of the copper clad laminated board by the manufacturing method of this invention.

In general, when carrying out electrolytic plating by conveying a long conductive substrate by a roll-to-roll method, an electrolytic plating apparatus as shown in FIG. 1 is used.
Hereinafter, using this electrolytic plating apparatus 1, a long polyimide film with a metal thin film in which a metal thin film is formed on a surface of a long polyimide film by a sputtering method without using an adhesive is used on a long conductive substrate. The method for electrolytic plating of a long conductive substrate of the present invention will be described by taking as an example a method for producing a copper clad laminate by a rising method.

[Electrolytic plating equipment]
As shown in FIG. 1, a roll-to-roll electrolytic plating apparatus 1 for carrying out the method of the present invention comprises a plating tank 11, an unwinding roll 12, a transporting guide roll 13, an insoluble anode (hereinafter, described) 14a to 14h), winding roll 15, and power supply rolls 16a to 16e. Note that F is a long polyimide film with a metal thin film (long conductive substrate), and S is a copper-coated long polyimide film (copper-clad laminate).

Here, the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h constitute an electrically independent electrolytic plating cell. Therefore, the surface of the metal film of the long polyimide film F with a metal thin film (for example, the conductive layer in the long conductive substrate) is in contact with the power supply rolls 16a, 16b, 16c, 16d, and 16e, so that the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h generate a potential difference, and electrolytic plating is performed.
Each anode may be either a soluble anode or an insoluble anode. Further, as can be seen from FIG. 1, each anode is a long polyimide film with a metal thin film (long conductive substrate) to be conveyed. Are arranged to face each other.

  In the production of a copper-clad laminate, copper electrolytic plating is performed to form a copper plating film layer. Therefore, a copper plate that dissolves and becomes a source of copper ions can be used if it is a soluble anode. Also, if an insoluble anode is used, a metal anode such as platinum or lead, or a ceramic anode obtained by coating a titanium frame with a conductive ceramic such as iridium oxide, rhodium oxide, or ruthenium oxide. A copper ion supply source may be provided outside the electrolytic plating tank.

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 metal thin film (long conductive substrate). Similarly, the anodes 14b, 14c, 14d, 14e, 14f, 14g, and 14h constitute an electrolytic plating 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 electrolytic plating layer.
Moreover, the electroplating apparatus 1 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 metal thin film (long conductive substrate), Various known devices such as stirring and supply of the plating solution can also be added.

In the electroplating apparatus 1 shown in FIG. 1, the plating tank 11 is filled with an acidic plating solution mainly composed of sulfuric acid and copper sulfate.
The long polyimide film F with a metal thin film (long conductive substrate) is unwound and conveyed from the unwinding roll 12 with the width direction being substantially horizontal, and is immersed in the plating solution of the plating tank 11 by the power supply roll 16a. Thus, the conveyance direction can be changed, and the conveyance direction can be changed to the plating liquid surface direction of the plating tank 11 by being reversed by the conveyance guide roll 13 in the plating 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 the electroplating is completed, it becomes a copper-clad laminate) is taken up by the take-up roll 15.

  The electrolytic plating apparatus 1 is an apparatus of a type in which a long polyimide film F with a metal thin film (long conductive substrate) is vertically immersed in a plating solution, but a long polyimide film F with a metal thin film F (long conductive substrate). ) Is not limited to the vertical direction, but may be immersed obliquely in the plating solution in the plating tank 11, and a long polyimide film F with a metal thin film F (long The direction in which the conductive substrate) is immersed can be selected as appropriate.

  However, when electrolytic plating is carried out using the electroplating apparatus 1 shown in FIG. 1 while conveying a long conductive substrate (long polyimide film F with a metal foil film in FIG. 1), the following problems occur. It was happening.

[Conveyance of long conductive substrates and problems]
The long conductive substrate (long polyimide film F with metal thin film) is transported in the electroplating apparatus 1 to form a copper electrolytic plating layer having a desired film thickness on the surface of the copper thin film layer. The long conductive substrate (long polyimide film F with a metal thin film) needs to be subjected to electrolytic plating with all the anodes provided in the electrolytic plating apparatus 1.

  Usually, when the electroplating apparatus 1 is operated in advance, a long conductive substrate (polyimide film F with a metal thin film) is set in the transport path and the operation is started. The long conductive substrate (long polyimide film F with a metal thin film) disposed downstream from the anode) is unable to form a copper plating at a desired film thickness, resulting in product loss, The problem arises that the rate and economy are compromised.

What is more problematic than this problem is the problem of seizure between the discoloration of the copper electrolytic plating layer, the power supply roll, etc. and the long conductive substrate (long resin film F with metal thin film).
Usually, the film thickness of the copper thin film layer of the long electroconductive board | substrate (long polyimide film F with a metal thin film) to be used is 50 nm-1000 nm, The resistance value per unit area is 10 < ^-1 > (omega | ohm).
Since the electroplating apparatus 1 is controlled by each anode and each power supply roll so that the current increases as it proceeds downstream (unloading side: take-up roll 15 side), a long conductive substrate (length with metal thin film) If the polyimide film F) is preliminarily mounted on the electroplating apparatus 1 and the operation is started, depending on the position of the power supply roll or the like, a large excess current may flow in the copper thin film layer, which may cause discoloration of the copper electroplating layer In the worst case, a seizure defect between the power supply roll or the like and the long conductive substrate (long resin film F with a metal thin film) will occur.

Therefore, in order to prevent these problems, a long insulating substrate (e.g., a PET film) is provided at the tip of the substrate when the long conductive substrate (long polyimide film F with metal thin film) is carried into the electroplating apparatus 1. A so-called dummy substrate is connected and provided at the top of the long conductive substrate so that the long conductive substrate (long polyimide film F with a metal thin film) is placed at a position where it does not contact the first power supply roll 16a. Electroplating is started by setting the long insulating substrate thus obtained as a guide.
In such an arrangement, since the long conductive substrate (long polyimide film F with a metal thin film) is guided by the long insulating substrate and conveyed in the electroplating apparatus 1, it is steady from the first power supply roll 16a. In this state, the electrolytic plating can be performed, and the film thickness of the copper plating film layer is gradually increased, so that a large excess current is not applied, and these problems do not occur.

The connection part of a long conductive substrate such as the long polyimide film F with a metal thin film and a long insulating substrate such as a PET film has a configuration shown in the schematic cross-sectional view of FIG.
FIGS. 2A and 2B are different from each other in how the long conductive substrate and the long insulating substrate are superposed, and FIG. 2A shows the long insulating property on the power supply roll contact surface side of the long conductive substrate. The case where the board | substrate has overlapped is shown, (b) shows the case where the long insulating board | substrate has overlapped with the base material side surface of the long electroconductive board | substrate.

The connection part 20 has an end part 21 of a long conductive substrate (long polyimide film F with a metal thin film F) and an end part 22 of a long insulating substrate to form step parts 23a and 23b. The step portions 23a and 23b constituted by 21 and 22 are covered with an adhesive tape 24A (covering portion covering the feeding roll contact surface side) and an adhesive tape 24B (covering portion covering the opposite surface side of the feeding roll contact surface). It has been broken.
In the connection part 20, the long electroconductive board | substrate (long polyimide film F with a metal thin film) and the long insulating board | substrate (PET film) may be bonded together with the double-sided adhesive tape 25 (refer Fig.2 (a)). If the mechanical strength of the connecting portion can be maintained as shown in FIG. 2B, the double-sided adhesive tape is not necessary.

An adhesive layer and a metal foil (for example, a copper foil) were laminated on the adhesive tape 24A that adheres to the conductive layer (copper thin film layer of the long polyimide film F with a metal thin film) surface of the long conductive substrate in contact with the power supply roll. It is desirable to cover the step portions 23a and 23b of the connecting portion 20 formed by the long conductive substrate (long polyimide film F with metal thin film) and the long insulating substrate using an adhesive tape.
In particular, since the conductive layer (copper thin film layer) is in contact with the power supply roll and is energized, the use of a conductive adhesive tape for the connecting portion 20 can be expected to have an effect of stabilizing the energization and suppressing abnormal discharge.

A plurality of steps are formed on both surfaces of the connecting portion 20 by a long conductive substrate (long polyimide film F with a metal thin film), a long insulating substrate, an adhesive tape, etc., but the conductive surface is a surface in contact with the power supply roll. It is desirable that the step difference from the surface of the layer (the surface of the copper thin film layer) does not exceed 100 μm.
If the level difference exceeds 100 μm, it may be transferred to the wound copper-clad laminate, and the copper-clad laminate may be deformed. On the other hand, since no current flows on the resin substrate (polyimide) side on the back side, there is no fear of abnormal discharge due to a step.
Furthermore, the layer thickness (total thickness of the adhesive layer and the base material (metal foil)) of the adhesive tape on the conductive layer (copper thin film layer) side is desirably 40 μm or less.

Further, the coating layer 26 may be provided on the surface on the conductive layer (copper thin film layer) side of the long conductive substrate, that is, the surface in contact with the power supply roll from the stepped portions 23a and 23b in the direction opposite to the transport direction.
As the coating layer 26, the pressure-sensitive adhesive tape used for coating the stepped portion (23b in FIG. 2A and 23a in FIG. 2B) may be used continuously, or may be coated separately.
Thus, in the connection portion, the conductive layer (copper thin film layer) of the long conductive substrate (long polyimide film F with metal thin film) is the stepped portion 23b formed by the long insulating substrate, or the long conductive substrate. Is covered with a coating layer in the reverse conveying direction (direction indicated by the black arrow in FIG. 2) from the stepped portion 23a formed by the stepped portion. It is possible to relax the dissolution of copper in the conductive layer (copper thin film layer). In addition, the length of the coating layer for obtaining the above effect may be appropriately determined in consideration of the loss amount of the electrolytic plating layer at the time of electrolytic plating.
Further, the adhesive layer of the conductive adhesive tape is a conductive adhesive layer formed by kneading conductive particles such as carbon in an adhesive.

  Such a connection portion is not only provided at the front end of the long conductive substrate shown in FIG. 2 but also when connecting long conductive substrates to handle a longer long conductive substrate. Moreover, a favorable electroplating layer can be brought about by utilizing for the connection part of the elongate conductive substrates.

[Long insulation substrate]
The long insulating substrate is exemplified by a PET film, but the material is not limited to a PET film, and can be cut even when immersed in an electroplating solution with flexibility that can be conveyed by a roll-to-roll method. It is sufficient to have a low mechanical strength, and it is appropriately selected from a polyester film such as PET, a polyimide film, a polyamide film, a polytetrafluoroethylene film, a resin film such as a polyphenylene sulfide film, and the like. Of these, PET films are commercially inexpensive and easily available.
Moreover, the thickness of a long insulating board | substrate should just be equipped with the thickness of a long conductive board | substrate, and the softness | flexibility which can be conveyed by a roll-to-roll system, and is 0.3-5 times the thickness of a long conductive board | substrate. The range can be selected as appropriate.

[Power supply start time]
However, even if such a long conductive substrate (long polyimide film F with a metal thin film) is transported, there are portions where minute convex concentration portions are generated in the copper electroplating layer.
Considering the location of the concentrated portion of the micro-convex, if the timing of starting energization to the opposing anode after the long conductive substrate (long polyimide film F with metal thin film) is immersed is delayed in the electrolytic plating bath A non-energized period occurs. As a result, the conductive roll (copper thin film layer) dissolves and the roll surface passing through is contaminated, and contaminants are transferred to the subsequent electrolytic copper plating layer. Was thought to occur.
On the other hand, if energization is started before immersion, the copper film will not be dissolved, but excessive current will cause the substrate to burn, and spark will occur at the feed roller.

Therefore, FIG. 3 is a schematic diagram for explaining the energization timing, (a) is a diagram showing a case where the conductive layer tip of the long conductive substrate is immersed in the electrolytic plating solution, and (b) is a diagram where the conductive layer tip is opposed. It is a figure which shows the time of moving the distance to 10% of the anode length of an anode, and the case of the first anode 14a of the plating apparatus 1 is shown. In addition, the relationship of the energization timing in another anode is demonstrated similarly. Reference numeral 16a denotes a power supply roll.
When the process of immersion and energization is examined with reference to FIG. 3, a long conductive substrate (long polyimide film F with metal thin film) 31 transported with a long insulating substrate 32 such as a PET film at the top is electroplated. In the process of being immersed in the tank 11, an exposed surface (not shown) in which the covering portion (26 in FIG. 2) at the tip of the conductive layer (copper thin film layer) is interrupted after the connection portion 30 of both is immersed in the electrolytic plating solution 37. 3) is immersed (FIG. 3 (a)).

The energization timing with the opposing anode 14a is after the exposed surface where the coating portion (26 in FIG. 2) at the tip of the conductive layer (copper thin film layer) is interrupted is immersed in the electrolytic plating solution (state of FIG. 3 (a)). It is desirable to energize while moving the distance up to 10% of the anode length (state shown in FIG. 3B).
For example, if the length of the anode is 2 m, the exposed surface where the coating portion (26 in FIG. 2) at the tip of the conductive layer (copper thin film layer) is interrupted is transported by 20 cm to the opposing anode after being immersed for the first time. That is, energization is started in the meantime.
The more desirable maximum value of the start timing of energization to the anode is that the exposed surface where the covering portion (26 in FIG. 2) at the tip of the conductive layer (copper thin film layer) is interrupted is electroplated even if the opposing anode exceeds 2 m. After being immersed in the liquid, it is being conveyed 20 cm to the opposing anode.

  A long conductive substrate (long polyimide film F with a metal thin film) that has been repeatedly immersed in the electrolytic plating solution in the electroplating apparatus 1 is not energized with the anode before energization with the opposing anode. Therefore, the potential may be on the positive side with respect to the electrolytic plating solution, and the surface of the conductive layer (copper thin film layer) is dissolved if copper electrolytic plating has already been performed. As a result, the power supply roll through which the long conductive substrate passes is contaminated with the melted copper thin film layer, and when it is transferred, a minute convex concentrated portion is generated.

  Therefore, in the electroplating method by the roll-to-roll method such as the electroplating apparatus 1, each time the long conductive substrate (long polyimide film F with a metal thin film) is immersed, the energization timing of each facing anode is It is desirable that the exposed surface where the coating portion (26 in FIG. 2) at the tip of the conductive layer (copper thin film layer) is interrupted moves a distance of up to 10% of the anode length of the opposing anode. .

  The energization start timing of each anode is determined by the length of the anode with respect to the opposing anode after the exposed surface where the coating portion (26 in FIG. 2) at the tip of the conductive layer (copper thin film layer) is interrupted is immersed in the electrolytic plating solution By moving the distance up to 10% of the distance, it is possible to prevent the occurrence of a minute convex concentration portion that may occur at each anode. If the end of the long conductive substrate passes through the opposing anode, the energization may be terminated.

  So far, the method of electrolytic plating of the long conductive substrate of the present invention has been described by taking the method of manufacturing a copper clad laminate as an example. However, the long conductive substrate used in the electrolytic plating method of the present invention is a metal thin film. The present invention is not limited to the attached long polyimide film or the copper clad laminate, and the same applies to a long metal foil or a metal strip. In the case of electrolytic plating of a substrate in which the entire substrate, as well as the front and back surfaces, as well as metal foil, is electroplated according to the method of electroplating a long conductive substrate of the present invention on the surface in contact with the power supply roll, the connecting portion is connected with a conductive adhesive tape May be formed.

[Copper laminate]
The copper-clad laminate 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 a 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 metal thin film 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 clad laminate 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 step is 50 to 1000 nm, and is generally 50 nm to 500 nm in terms of productivity.

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

A chamber in which a vacuum is maintained at 0.01 to 0.1 Pa on this polyimide film using “Kapton (registered trademark) 150EN (thickness: 38 μm)” manufactured by Toray DuPont Co., Ltd. having a width of 50 cm for a long polyimide film. Heat treatment was performed at 150 ° C. for 1 minute.
Subsequently, a base metal layer containing 20% by weight of chromium is formed on the polyimide film by sputtering to a thickness of 20 nm, and a copper thin film layer is formed to a thickness of 100 nm to form a long polyimide film F with a metal thin film (long conductive substrate). )
A roll-to-roll type sputtering apparatus was used for sputtering.

After sputtering, on the obtained long polyimide film F with metal thin film (long conductive substrate), a copper layer having a thickness of 8 μm is formed as a copper electrolytic plating layer by an electrolytic plating method using the electrolytic plating apparatus 1 shown in FIG. Formed.
The basic composition of the electrolytic plating solution used was 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.
A soluble copper anode was used for the anode provided facing the substrate to be transported, and the length of the anode with respect to the transport direction of the long polyimide film F with a metal thin film (long conductive substrate) was 2 m. The current density of each anode was as shown in Table 1.

When the 8 μm thick copper electrolytic plating layer was thickened by the electrolytic plating method, the timing of starting energization with each anode was set to 4 cm (2% of the length of the anode) in the plating step.
As a result of measuring the micro-convex of the produced copper-clad laminate with a microscope, there is no concentration of micro-convex in altitude difference 0.2 to 1.0 μm, horizontal distance 1 to 30 μm, and good results to clear the characteristic inspection Got. The number of samples is 500.

A copper-clad laminate was obtained in the same manner as in Example 1 except that the energization start timing with each anode was 20 cm (10% of the length of the anode).
As a result of measuring the small convexity of the produced copper clad laminate, there is no concentration of minute convexity between 0.2 to 1.0 μm in height difference and 1 to 30 μm in horizontal distance, and good results that clear the characteristic inspection are obtained. It was. The number of samples is 500.

(Comparative Example 1)
A copper-clad laminate was obtained in the same manner as in Example 1 except that the energization start timing with each anode was 30 cm (15% of the length of the anode). As a result of measuring the convexity of the copper-clad laminate, the height difference was 0.2 to 1.0 μm, and the horizontal distance was 1 to 30 μm. Concentration of microconvex occurred, and the characteristic inspection could not be cleared.

(Comparative Example 2)
A copper-clad laminate was obtained in the same manner as in Example 1 except that the energization start timing with each anode was −4 cm (energization before being immersed).
As a result of measuring the minute protrusions of the copper clad laminate, the height difference was 0.2 to 1.0 μm, and the horizontal distance was 1 to 30 μm. Concentration of the minute protrusions occurred, and the characteristic inspection could not be cleared. Moreover, since the dent of a roller period generate | occur | produced by spark generation, it could not be set as a product.

  The copper-clad laminate of the present invention is used for flexible printed wiring boards.

DESCRIPTION OF SYMBOLS 1 Electrolytic plating apparatus 2 Polyimide film 3 Underlying metal layer 4 Copper thin film layer 5 Copper plating film layer 6 Metal thin film layer 11 Plating tank 12 Unwinding roll 13 Conveyance rolls 14a-14h (insoluble) Anode 15 Winding roll 16a -16e Feeding roll 20 Connection portion 21 Long conductive substrate (long polyimide film with metal thin film) end portion 22 Long insulating substrate (PET film) end portion 23a (formed by the long conductive substrate) Step portion 23b Step portion 24A (covered by the long insulating substrate) (covering portion covering the feeding roll contact surface side) adhesive tape 24B (covering portion covering the opposite side of the feeding roll contact surface) adhesive tape 25 double-sided adhesive tape 26 Covering portion 30 covering the feeding roll contact surface side of the long conductive substrate Connection portion 31 Long conductive substrate 32 Long insulating substrate 37 Electrolytic plating solution F Metal thin film length Length polyimide film (long conductive substrate)
S Copper-coated long polyimide film (copper-clad laminate)

Claims (5)

A long conductive substrate having a conductive surface is transported by a roll-to-roll method, and a plurality of anodes are provided at positions facing the long conductive substrate along a transport path of the long conductive substrate. In the method of electroplating a long conductive substrate, by repeatedly immersing in an electrolytic plating solution filled in an electroplating tank, and performing electroplating on the surface of the conductive layer of the long conductive substrate,
The long conductive substrate is provided with a long insulating substrate via a connecting portion at a tip portion on the transport direction side, and is transported to the electrolytic plating tank by the long insulating substrate leading,
After the long insulating substrate and the connecting portion are immersed in the electrolytic plating solution, the length of the anode facing the conductive layer tip from when the conductive layer tip of the long conductive substrate is immersed in the electrolytic plating solution The electroplating method for a long conductive substrate is characterized in that energization of the opposing anode is started while moving a distance of 2% to 10%. The long conductive substrate is provided with an electroplating process on the surface of the conductive layer by immersion in the electrolytic plating solution in the long conductive substrate and energization of the opposing anode along the transport path of the long conductive substrate. Performed for each of a plurality of anodes facing the substrate,
The energization of the facing anode moves a distance from 2% to 10% of the length of the facing anode when the leading edge of the conductive layer of the long conductive substrate is immersed in the electrolytic plating solution. 2. The method for electroplating a long conductive substrate according to claim 1, wherein energization of the opposing anode is started during the process.   The method of electrolytic plating of a long conductive substrate according to claim 1 or 2, wherein the electrolytic plating solution is a copper plating solution.   The long conductive substrate is a long resin film with a metal thin film laminated in order of a base metal layer made of a nickel alloy thin film and a copper thin film layer on the surface of the long resin film without using an adhesive. The electrolytic plating method for a long conductive substrate according to any one of claims 1 to 3. A method for producing a copper-clad laminate in which an electrolytic plating film layer is provided on the surface of a long conductive substrate by an electrolytic plating method,
The said electrolytic plating method is the electrolytic plating method of the elongate conductive substrate of Claim 4, The manufacturing method of the copper clad laminated board characterized by the above-mentioned.

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