阅读说明：本技术 层压体的制造方法 (Method for producing laminate ) 是由 福岛和宏 于 2020-12-04 设计创作，主要内容包括：本发明公开了一种层压体的制造方法,层压体(13)由铜箔(10)和绝缘性聚合物(12)层压而成,该层压体的制造方法包括：利用溅射法在真空室内在铜箔的表面上形成铜扩散阻挡层的工序(A)、以及将绝缘性聚合物层压在表面已形成有铜扩散阻挡层的铜箔上的工序(B)。工序(A)包括将水蒸气引入真空室内,在铜扩散阻挡层的表面上形成构成该铜扩散阻挡层的金属的氢氧化物的工序。因此,本发明提供一种层压体的制造方法,在铜箔的表面粗糙度较小的情况下也能充分地确保铜箔和绝缘性聚合物间的黏合性。(The invention discloses a method for manufacturing a laminated body, wherein the laminated body (13) is formed by laminating a copper foil (10) and an insulating polymer (12), and the method for manufacturing the laminated body comprises the following steps: the method comprises a step (A) of forming a copper diffusion barrier layer on the surface of a copper foil in a vacuum chamber by sputtering, and a step (B) of laminating an insulating polymer on the copper foil having the copper diffusion barrier layer formed on the surface. The step (a) includes a step of introducing water vapor into the vacuum chamber to form a hydroxide of a metal constituting the copper diffusion barrier layer on the surface of the copper diffusion barrier layer. Accordingly, the present invention provides a method for producing a laminate capable of sufficiently securing adhesion between a copper foil and an insulating polymer even when the surface roughness of the copper foil is small.)

1. A method for producing a laminate comprising a copper foil and an insulating polymer, characterized in that:

the method for manufacturing the laminated body comprises the following steps: a step (A) of forming a copper diffusion barrier layer on the surface of the copper foil in a vacuum chamber by a sputtering method, and a step (B) of laminating the insulating polymer on the copper foil having the copper diffusion barrier layer formed on the surface thereof,

the step (A) includes: and a step of introducing water vapor into the vacuum chamber to form a hydroxide of the metal constituting the copper diffusion barrier layer on the surface of the copper diffusion barrier layer.

2. The method of manufacturing a laminated body according to claim 1, characterized in that:

the step (A) includes a step of applying a silane coupling agent to the surface of the hydroxide.

3. The method of manufacturing a laminated body according to claim 1 or 2, characterized in that:

the metal forming the copper diffusion barrier layer is nickel or a nickel alloy containing chromium.

4. The method of manufacturing a laminated body according to claim 1 or 2, characterized in that:

in the step (a), the hydroxide covers 50% or more of the surface of the copper diffusion barrier layer.

5. The method of manufacturing a laminated body according to claim 2, characterized in that:

the step of applying the silane coupling agent on the surface of the hydroxide is performed by introducing the silane coupling agent vapor into a vacuum chamber,

in the step (a), the step of forming the copper diffusion barrier layer on the surface of the copper foil, the step of forming the hydroxide on the surface of the copper diffusion barrier layer, and the step of applying the silane coupling agent on the surface of the hydroxide are continuously performed in the same vacuum chamber.

6. The method of manufacturing a laminated body according to claim 1, characterized in that:

the step (B) includes a step of performing plasma treatment on the surface of the insulating polymer,

in the step (B), the surface of the insulating polymer which has been subjected to the plasma treatment is made to face the copper diffusion barrier layer, and the insulating polymer is laminated on the surface of the copper diffusion barrier layer.

Technical Field

The present invention relates to a method for producing a laminate comprising a copper foil and an insulating polymer laminated thereon.

Background

Most of the flexible wiring substrates are constituted by a laminate formed by hot-pressing a copper foil and an insulating polymer. The circuit pattern is formed by etching the copper foil of the laminate.

When the flexible wiring board is used at a high temperature for a long time, the adhesion between the copper foil and the insulating polymer is degraded by the diffusion of copper constituting the copper foil into the insulating polymer. In order to prevent this, a copper diffusion barrier layer is interposed between the copper foil and the insulating polymer.

In order to improve the adhesion between the copper foil and the insulating polymer, the surface of the copper foil is roughened (patent document 1), or a silane coupling agent is applied to the surface of the copper foil (patent document 2). The surface of an insulating polymer is subjected to plasma treatment (patent document 3).

Patent document 1: japanese laid-open patent publication No. 2004-25835

Patent document 2: japanese laid-open patent publication No. 2015-13474

Patent document 3: japanese laid-open patent publication No. 2005-324511

Disclosure of Invention

Technical problems to be solved by the invention

If the surface of the copper foil is roughened, the current flowing through the wiring is concentrated on the surface of the copper foil by the skin effect, and the transmission loss increases, which hinders the high frequency of the device.

However, if the plane of the copper foil is made flat, the anchor effect (anchor effect) is reduced. The anchoring effect is decreased and the adhesion between the copper foil and the insulating polymer is decreased. In particular, if the surface roughness of the copper foil is reduced to about 1 μm in order to suppress the transmission loss at a high frequency exceeding several GHz, there is a problem as follows: only by applying a silane coupling agent to the surface of a copper foil or by plasma-treating the surface of an insulating polymer in the prior art, the adhesion between the copper foil and the insulating polymer cannot be sufficiently ensured.

The present invention has been made to solve the above problems, and an object of the present invention is to: provided is a method for producing a laminate, which can sufficiently ensure the adhesion between a copper foil and an insulating polymer even when the surface roughness of the copper foil is small.

Technical solutions for solving technical problems

The method for producing a laminate according to the present invention is a method for producing a laminate comprising a copper foil and an insulating polymer laminated thereon, the method for producing the laminate comprising: the method comprises a step (A) of forming a copper diffusion barrier layer on the surface of a copper foil in a vacuum chamber by sputtering, and a step (B) of laminating an insulating polymer on the copper foil having the copper diffusion barrier layer formed on the surface. The step (a) includes a step of introducing water vapor into the vacuum chamber to form a hydroxide of a metal constituting the copper diffusion barrier layer on the surface of the copper diffusion barrier layer.

Effects of the invention

According to the present invention, it is possible to provide a method for producing a laminate which can sufficiently ensure adhesion between a copper foil and an insulating polymer even when the surface roughness of the copper foil is small.

Drawings

Fig. 1(a) to (D) schematically show a method for manufacturing a laminate in an embodiment of the present invention;

fig. 2(a) to (D) schematically show a method of manufacturing a laminate in other embodiments of the present invention;

FIG. 3 illustrates a method of forming a laminate in a roll-to-roll manner;

FIG. 4 illustrates a method of laminating a roll of treated copper foil and an insulating polymer in a roll-to-roll manner;

FIG. 5 illustrates a method of laminating a roll of treated copper foil and an insulating polymer in a roll-to-roll manner;

FIG. 6 illustrates a method of laminating a treated copper foil roll and an insulating polymer in a roll-to-roll melt casting process;

fig. 7 shows a method of laminating a treated copper foil roll and an insulating polymer in a roll-to-roll melt casting method.

-description of symbols-

10-copper foil; 10A-untreated copper foil roll; 10B-a treated copper foil roll; 11-a copper diffusion barrier layer; 12-an insulating polymer; 13-a laminate; 13A-laminate roll; 20-sputtering apparatus (vacuum chamber); 21a to 21 g-transport rollers; 22a, 22b, 22 c-cathode; 23-a target material; 24-a water vapor supply source; 24 a-a water container; 24 b-liquid mass flow controller; 24 c-a heated vaporizer; 24 d-nozzle; a 25-silane coupling agent supply source; 25 a-a silane coupling agent container; 25 b-liquid mass flow controller; 25 c-a heated vaporizer; 25 d-nozzle; 26-a pretreatment part; 27-a partition wall; 30-a hot-pressing roller; 31-a chill roll; 40-atmospheric pressure plasma device; 41-a heater; 50-a casting drum; 51-die; 60-a roller; 61-casting belt; 62-die; 63-curing zone.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the following embodiments. The present invention can be modified as appropriate without departing from the scope of the present invention.

Fig. 1(a) to (D) schematically show a method for producing a laminate according to an embodiment of the present invention.

As shown in fig. 1a, a copper diffusion barrier layer 11 is formed on the surface of a copper foil 10 in a vacuum chamber (not shown) by a sputtering method. Here, the average roughness (Rz) of the surface of the copper foil 10 is preferably 1.5 μm or less, more preferably 1.0 μm or less, which can suppress transmission loss even at a high frequency of about 10 GHz.

The material of the copper diffusion barrier layer 11 preferably contains at least one metal selected from nickel, chromium, cobalt, manganese, titanium, and the like. In particular, for reasons described below, it is preferable to use nickel or a nickel alloy containing chromium as the material of the copper diffusion barrier layer 11.

If the thickness of the copper diffusion barrier layer 11 is too thick, there is a possibility that etching failure may occur when a circuit pattern is formed; if the thickness of the copper diffusion barrier layer 11 is too thin, the copper diffusion barrier property may be insufficient. Therefore, the thickness of the copper diffusion barrier layer 11 is preferably in the range of 10nm to 50nm, more preferably in the range of 20nm to 30 nm.

In the present embodiment, in the step of forming the copper diffusion barrier layer 11 on the surface of the copper foil 10 by sputtering, water vapor is introduced into a vacuum chamber (not shown) to form a hydroxide (not shown) of the metal constituting the copper diffusion barrier layer 11 on the surface of the copper diffusion barrier layer 11. For example, when the copper diffusion barrier layer 11 is formed using nickel, nickel hydroxide (Ni (OH)) is formed on the surface of the copper diffusion barrier layer 11₂)。

The water vapor may also be bubbled with argon and the bubbled water vapor introduced into the vacuum chamber. In this way, a small amount of water vapor, of the order of only a few atomic% relative to argon, can be easily introduced into the vacuum chamber. Further, the water quantified by the liquid mass flow controller is converted into water vapor by the vaporizer and introduced into the vacuum chamber from the nozzle, whereby the partial pressure of the water vapor can be stabilized. In either method, water vapor is introduced into the vacuum chamber as superheated water vapor, so that water molecules are introduced into the vacuum chamber as single molecules, rather than as clusters. As a result, OH radicals can be generated with good efficiency by activating water molecules with plasma.

Preferably, the introduction of the water vapor is performed on the downstream side of the atmosphere in which the copper diffusion barrier layer 11 is formed by the sputtering method. This enables stable formation of hydroxide on the surface of the copper diffusion barrier layer 11.

Next, as shown in fig. 1B, a silane coupling agent is applied to the surface of the hydroxide (not shown) formed on the surface of the copper diffusion barrier layer 11. The silane coupling agent is not particularly limited, and for example, an epoxy-functional silane coupling agent, an amino-functional silane coupling agent, a mercapto-functional silane coupling agent, a vinyl-functional silane coupling agent, a methacrylic-functional silane coupling agent, an acrylic-functional silane coupling agent, an imidazole-based silane coupling agent, a triazine-functional silane coupling agent, and the like can be used.

The step of applying the silane coupling agent to the surface of the hydroxide can be performed by, for example, introducing a silane coupling agent vapor into a vacuum chamber (not shown). Thus, the step of forming the copper diffusion barrier layer 11 on the surface of the copper foil 10, the step of forming the hydroxide on the surface of the copper diffusion barrier layer 11, and the step of applying the silane coupling agent on the surface of the hydroxide can be continuously performed in the same vacuum chamber.

Preferably, in this case, the introduction of the silane coupling agent vapor is performed on the downstream side of the ambient gas into which the water vapor is introduced. Thus, the silane coupling agent can be stably applied to the surface of the hydroxide.

The silane coupling agent vapor is introduced into the vacuum chamber from the nozzle after the silane coupling agent quantified by the liquid mass flow controller is converted into vapor by the vaporizer, so that the partial pressure of the silane coupling agent vapor can be stabilized.

At this time, since the pressure of the silane coupling agent vapor is lower than the pressure of the water vapor, the silane coupling agent vapor can be stably introduced into the vacuum chamber by heating the nozzle. However, the heating temperature of the nozzle is preferably a temperature at which the silane coupling agent is not thermally decomposed, and is about 250 ℃ or lower.

The step of applying the silane coupling agent to the surface of the hydroxide may be performed by applying a solution containing the silane coupling agent to the surface of the copper diffusion barrier layer 11.

Next, as shown in fig. 1(C), an insulating polymer 12 is laminated on the copper foil 10 having the copper diffusion barrier layer 11 formed on the surface thereof. As shown in fig. 1(D), a laminate 13 of the copper foil 10 and the insulating polymer 12 is formed. The lamination of the copper foil 10 and the insulating polymer 12 can be performed by, for example, a lamination method (hot press), a melt casting film forming method, a solution casting film forming method, or the like.

The insulating polymer 12 is not particularly limited, and examples of the thermoplastic polymer include liquid crystal polymers, polyphenylene sulfide, cycloolefin polymers, perfluoroalkoxy fluororesins, tetrafluoroethylene-hexafluoropropylene copolymers, and ethylene-tetrafluoroethylene copolymers. Examples of the non-thermoplastic polymer include polyimide, aromatic polyamide, and cycloolefin polymer.

According to the present embodiment, by forming a hydroxide on the surface of the copper diffusion barrier layer 11, a functional group (hydrophilic group) that is a hydroxyl group (OH group) can be introduced into the surface of the copper diffusion barrier layer 11. When a silane coupling agent is applied to the surface of the copper diffusion barrier layer 11, OH groups introduced into hydroxyl groups (hydrophilic groups) on the surface of the copper diffusion barrier layer 11 and silanol groups (SiOH groups), which are hydrophilic groups of the silane coupling agent, are bonded, and hydrophobic groups such as vinyl groups, epoxy groups, methacrylic groups, mercapto groups, and amino groups, which are easily bonded to the insulating polymer, are present on the surface of the copper diffusion barrier layer 11 coated with the silane coupling agent.

As described above, when the copper foil 10 having the copper diffusion barrier layer 11 formed on the surface thereof and the insulating polymer 12 are laminated by hot pressing or the like, silanol groups of the silane coupling agent and OH groups on the surface of the copper diffusion barrier layer 11 undergo dehydration condensation polymerization, and the hydrophobic groups react with functional groups on the surface of the insulating polymer 12. Therefore, the adhesion between the copper diffusion barrier layer 11 and the insulating polymer 12 can be improved. As a result, even when the surface roughness of the copper foil 10 is small, the laminate 13 in which the adhesiveness between the copper foil 10 and the insulating polymer 12 is sufficiently secured can be obtained.

In the present embodiment, water vapor is introduced into the vacuum chamber to form a hydroxide of the metal constituting the copper diffusion barrier layer 11 on the surface of the copper diffusion barrier layer 11. As the metal forming the copper diffusion barrier layer 11, nickel or a nickel alloy containing chromium, which is likely to form a hydroxide, is preferably used. When a nickel alloy containing chromium is used, the copper diffusion barrier property and the etching property can be improved by making the nickel content 80% or more.

When the thickness of the hydroxide is increased to form a circuit pattern, etching failure may occur. Therefore, the thickness of the hydroxide is preferably 10nm or less, more preferably 5nm or less.

The hydroxide does not necessarily have to cover the entire copper diffusion barrier layer 11. However, in order to sufficiently bond the hydroxyl groups introduced into the surface of the copper diffusion barrier layer 11 and the silanol groups of the silane coupling agent, the hydroxide covers preferably 50% or more, more preferably 70% or more of the surface of the copper diffusion barrier layer 11. The amount of hydroxyl groups in the hydroxide can be quantified by a surface analysis method such as Fourier transform infrared spectroscopy (FT-IR) or X-ray photoelectron spectroscopy (XPS).

If the introduced water vapor is excessive, the pressure in the vacuum chamber rises, and the water vapor is sucked as impurities throughout the sputtering process, so that the introduced water vapor is excessive and not preferable. Preferably, the pressure gauge is installed in the vicinity of the water vapor introducing portion, and the amount of water vapor introduced is set and managed.

(other embodiments)

In the above embodiment, the silane coupling agent is applied on the surface of the copper diffusion barrier layer 11 on which the hydroxide has been formed on the surface. However, the same effect can be obtained by performing plasma treatment on the surface of the insulating polymer 12 on the side to be bonded to the copper diffusion barrier layer 11 instead of applying the silane coupling agent.

Fig. 2(a) to (D) schematically show a method for producing a laminate according to another embodiment of the present invention. The same steps as those of the method for producing a laminate shown in (a) to (D) in fig. 1 will not be described in detail.

First, as shown in fig. 2a, a copper diffusion barrier layer 11 is formed on the surface of a copper foil 10 in a vacuum chamber (not shown) by a sputtering method. In the present embodiment, in the step of forming the copper diffusion barrier layer 11 by the sputtering method, water vapor is introduced into the vacuum chamber, and a hydroxide (not shown) of the metal constituting the copper diffusion barrier layer 11 is formed on the surface of the copper diffusion barrier layer 11.

Next, as shown in fig. 2(B), the surface 12a of the insulating polymer 12 is subjected to plasma treatment. In this way, functional groups (hydrophilic groups) such as hydroxyl groups (OH groups) and carboxyl groups (COOH groups) are introduced into the surface 12a of the insulating polymer 12.

The gas used for the plasma treatment is not particularly limited, and He, Ar, N, for example, can be used₂、O₂、CO₂Air, etc. If N is used₂Or air, the cost can be suppressed. By mixing water vapor into the plasma gas, hydroxyl groups are easily introduced into the surface 12a of the insulating polymer 12.

In the case where water vapor is used in the plasma gas, it is preferable to add the plasma gas Ar because the argon radicals dissociate water molecules of the water vapor in the plasma by the penning effect, promoting the generation of hydroxyl groups.

Next, as shown in fig. 2(C), the surface 12a of the insulating polymer 12 which has been subjected to the plasma treatment is opposed to the copper diffusion barrier layer 11, and the insulating polymer 12 is laminated on the surface of the copper diffusion barrier layer 11 by hot pressing or the like. As shown in fig. 2(D), a laminate 13 of the copper foil 10 and the insulating polymer 12 is formed.

According to the present embodiment, a hydroxyl group (OH group), i.e., a functional group (hydrophilic group), is introduced into the surface of the copper diffusion barrier layer 11 by forming a hydroxide on the surface of the copper diffusion barrier layer 11. On the other hand, by plasma treatment of the surface 12a of the insulating polymer 12, functional groups (hydrophilic groups) such as hydroxyl groups (OH groups) and carboxyl groups (COOH groups) are introduced into the surface 12a of the insulating polymer 12.

As described above, if the copper diffusion barrier layer 11 and the insulating polymer 12 are laminated by hot pressing or the like, the hydroxyl group (hydrophilic group) introduced into the surface of the copper diffusion barrier layer 11 and the hydroxyl group and the carboxyl group (hydrophilic group) introduced into the surface of the insulating polymer 12 are hydrogen-bonded. As a result, the adhesion between the copper diffusion barrier layer 11 and the insulating polymer 12 is improved. Even when the surface roughness of the copper foil 10 is small, the laminate 13 can be obtained in which the adhesion between the copper foil 10 and the insulating polymer 12 is sufficiently ensured.

In order to increase the effect of improving the adhesion between the copper diffusion barrier layer 11 and the insulating polymer 12, it is preferable that the hydroxyl group (hydrophilic group) introduced into the surface of the copper diffusion barrier layer 11 and the hydroxyl group and the carboxyl group (hydrophilic group) introduced into the surface of the insulating polymer 12 are sufficiently close to each other so as to allow intermolecular force to act. As a result, since the surface of the copper diffusion barrier layer 11 and the surface of the insulating polymer 12 each have irregularities larger than the intermolecular distance, it is preferable to apply pressure using a laminator or the like at the time of lamination.

When the insulating polymer 12 is heated to a temperature of not lower than the glass transition temperature but lower than the melting point at the time of lamination, the surfaces of the copper diffusion barrier layer 11 and the insulating polymer 12 are likely to be sufficiently close to each other, and therefore it is preferable to heat the insulating polymer 12 to a temperature of not lower than the glass transition temperature but lower than the melting point. The heating temperature is preferably 120 ℃ or higher, preferably 150 ℃ or higher, because the dehydropolycondensation reaction of the hydroxyl group is accelerated.

In the present embodiment, the plasma treatment step of the surface of the insulating polymer 12 and the lamination step of the copper diffusion barrier layer 11 and the insulating polymer 12 can be continuously performed under atmospheric pressure by performing the plasma treatment of the surface of the insulating polymer 12 using atmospheric pressure plasma.

If the dielectric barrier discharge is used as a method for generating the atmospheric pressure plasma, the insulating polymer 12 having a wide width can be uniformly processed without causing thermal damage. Therefore, the discharge is good with the dielectric barrier. When the inductively coupled plasma is used, it is easy to introduce active species such as hydroxyl groups at a high density, and therefore, it is preferable to use the inductively coupled plasma.

If the plasma treatment is performed in a state where the insulating polymer 12 has been heated to a temperature of not lower than the glass transition temperature but lower than the melting point, molecular motion of the amorphous portion is activated, and therefore functional groups generated by plasma are easily introduced into the surface of the insulating polymer 12. Therefore, it is preferable to perform the plasma treatment in a state where the insulating polymer 12 is heated to a temperature of not lower than the glass transition temperature but lower than the melting point.

It is not preferable that the laminate 13 is formed by applying a silane coupling agent to the copper diffusion barrier layer 11 having a hydroxide formed on the surface thereof, performing plasma treatment on the surface of the insulating polymer 12, and laminating the copper diffusion barrier layer 11 having a silane coupling agent applied to the surface thereof and the insulating polymer 12 having a plasma treated surface thereof by hot pressing or the like. The reason why this is not preferable is as follows.

As described above, in the case where the silane coupling agent has been applied to the copper diffusion barrier layer 11 having formed on the surface thereof a hydroxide, a hydrophobic group may exist on the surface of the copper diffusion barrier layer 11 due to bonding of a hydroxyl group (hydrophilic group) introduced into the surface of the copper diffusion barrier layer 11 and the hydrophilic group of the silane coupling agent. On the other hand, functional groups (hydrophilic groups) such as hydroxyl groups (OH groups) and carboxyl groups (COOH groups) are present on the surface 12a of the insulating polymer 12 that has been subjected to plasma treatment.

That is, a hydrophobic group that hinders adhesiveness exists on the surface of the copper diffusion barrier layer 11, and a hydrophilic group that hinders adhesiveness exists on the surface of the insulating polymer 12. Therefore, even if the copper diffusion barrier layer 11 whose surface has been coated with a silane coupling agent and the insulating polymer 12 whose surface has been subjected to plasma treatment are laminated by hot pressing or the like, it is difficult to obtain the laminated body 13 with improved adhesiveness.

(method of producing a roll-to-roll laminate)

Fig. 3 shows a method in which the step of forming the copper diffusion barrier layer 11 on the surface of the copper foil 10 by the sputtering method, the step of forming the hydroxide of the metal constituting the copper diffusion barrier layer 11 on the surface of the copper diffusion barrier layer 11, and the step of applying the silane coupling agent on the surface of the hydroxide are continuously performed in a sputtering apparatus (vacuum chamber) by a roll-to-roll method.

As shown in fig. 3, the sputtering apparatus 20 includes a transport drum 21a, and three cathodes 22a, 22b, 22 c. A nickel-chromium alloy (Ni 80: Cr20) is provided on the cathodes 22a, 22b, 22c as the target 23, and the cathodes 22a, 22b, 22c are connected to a sputtering power source (not shown). Argon gas is supplied to the vicinity of each of the cathodes 22a, 22b, 22c by a mass flow controller (not shown).

A nozzle 24d that introduces water vapor from the water vapor supply source 24 is disposed at a downstream portion of the cathode 22c located most downstream. This makes it easy to form a hydroxide only on the surface of the copper diffusion barrier layer 11. Therefore, it is preferable to arrange the nozzle 24d for introducing the water vapor from the water vapor supply source 24 at the downstream portion of the cathode 22c located most downstream. The water tank 24a, the liquid mass flow controller 24b, and the heating vaporizer 24c are connected in this order to constitute a water vapor supply source 24. If the nozzle 24d includes a heater for heating, it is possible to suppress a decrease in the nozzle temperature due to the removal of vaporization heat and condensation caused thereby.

A nozzle 25d for introducing silane coupling agent vapor from the silane coupling agent supply source 25 is disposed on the downstream side of the cathode 22c from the nozzle 24 d. The silane coupling agent supply source 25 is constituted by connecting a silane coupling agent container 25a, a liquid mass flow controller 25b, and a heating vaporizer 25c in this order.

If the nozzles 24d and 25d include heaters for heating, the decrease in the nozzle temperature due to the removal of the vaporization heat and the condensation caused thereby can be suppressed. The silane coupling agent does not necessarily cover the entire copper diffusion barrier layer 11, but if the silane coupling agent covers 50% or more, and more preferably 70% or more, of the surface of the copper diffusion barrier layer 11, the copper diffusion barrier layer 11 easily adheres to the insulating polymer 12. Therefore, the silane coupling agent preferably covers 50% or more, more preferably 70% or more, of the surface of the copper diffusion barrier layer 11.

Since the silane coupling agent supplied in a vapor state is preferentially adsorbed by the hydroxyl groups on the surface of the copper diffusion barrier layer 11, the copper diffusion barrier layer 11 easily adheres to the insulating polymer 12. Therefore, the silane coupling agent is preferably supplied in a vapor state.

The amount of the silane coupling agent can be quantified by a surface analysis method such as a Fourier transform infrared spectroscopy (FT-IR) method or an X-ray photoelectron spectroscopy (XPS) method. If the silane coupling agent is introduced in an excessive amount, the pressure in the vacuum chamber rises, and the silane coupling agent is sucked as impurities throughout the sputtering process, so that the introduced silane coupling agent in an excessive amount is not preferable. Preferably, a pressure gauge is disposed in the vicinity of the silane coupling agent introducing portion, and the introducing amount of the silane coupling agent vapor is set and managed.

After the untreated copper foil roll 10A is unwound from the transport drum 21B, a predetermined treatment is performed while the untreated copper foil roll 10A is received by the transport drum 21a, and the unwound untreated copper foil roll 10A is wound up as a treated copper foil roll 10B by the transport drum 21 c.

A pretreatment section 26 for pretreating the untreated copper foil roll 10A is disposed between the transport drum 21b and the most upstream cathode 22 a. A heater, a plasma source, or the like can be selected as the pretreatment unit 26.

The conveying drum 21b, the pretreatment unit 26, the cathodes 22a, 22b, and 22c, the nozzle 25d, and the conveying drum 21c are substantially partitioned by partition walls 27, and are independently evacuated by a vacuum pump (not shown).

Fig. 4 shows a method of laminating (hot pressing) the insulating polymer 12 on the treated copper foil roll 10B treated in the sputtering apparatus 20 shown in fig. 3 in a roll-to-roll manner.

As shown in fig. 4, the surface coated with the silane coupling agent of the treated copper foil roll 10B withdrawn from the transport drum 21 is opposed to the insulating polymer 12 withdrawn from the transport drum 21d, and in this state, the treated copper foil roll 10B and the insulating polymer 12 are laminated by a pair of hot press rolls 30, and are wound as a laminate roll 13A on the transport drum 21e via a cooling roll 31.

In the case where the silane coupling agent is not applied to the surface of the hydroxide formed on the copper diffusion barrier layer 11 by the sputtering apparatus 20 shown in fig. 3, the insulating polymer 12 can be laminated on the treated copper foil roll 10B treated by the sputtering apparatus 20 in a roll-to-roll manner by the apparatus shown in fig. 5.

As shown in fig. 5, the surface of the insulating polymer 12 which has exited from the transport drum 21d is subjected to plasma treatment by the atmospheric pressure plasma apparatus 40. After that, the surface of the treated copper foil roll 10B withdrawn from the transport drum 21 on which the hydroxide is formed is opposed to the surface of the insulating polymer 12 on which the plasma treatment has been performed, and in this state, the treated copper foil roll 10B and the insulating polymer 12 are laminated by a pair of hot press rolls 30, and are wound as a laminate roll 13A on the transport drum 21e via a cooling roll 31.

By providing the heater 41 upstream of the atmospheric pressure plasma device 40 and preheating the insulating polymer 12 to a temperature lower than the glass transition temperature or the softening temperature, the plasma treatment effect can be improved, and the adhesive force at the time of lamination can be improved.

Fig. 6 shows a method of laminating the insulating polymer 12 on the treated copper foil roll 10B which has been treated in the sputtering apparatus 20 shown in fig. 3 in a roll-to-roll manner by a melt casting method.

As shown in fig. 6, the treated copper foil roll 10B which is withdrawn from the transport drum 21c is fed to the cooled casting drum 50 with the treated surface as the non-drum side surface. Next, the thermoplastic insulating polymer 12 is cast from the die 51 onto the treated surface of the treated copper foil roll 10B. The thermoplastic insulating polymer 12 is rapidly cooled on the treated copper foil roll 10B, and wound as a laminate roll 13A on a transport drum 21 f.

Fig. 7 shows another method of laminating the insulating polymer 12 on the treated copper foil roll 10B treated by the sputtering apparatus 20 shown in fig. 3 in a roll-to-roll manner by a melt casting method.

As shown in fig. 7, the processed surface of the processed copper foil roll 10B that has exited from the transport drum 21c is a non-drum side surface, and the processed copper foil roll 10B is fed onto a casting belt 61 made of a seamless metal belt that is stretched over two drums 60. Then, a polymer solution is cast from a die 62 onto the treated surface of the treated copper foil roll 10B. The polymer solution is dried and cured in the curing zone 63, and then wound around the transport drum 21g as a laminate roll 13A.

The present invention has been described above with reference to preferred embodiments, but the above description is not limitative, and it is needless to say that various modifications can be made to the present invention.