JP2014222689A - Method and apparatus for manufacturing double-side metal laminated film, and manufacturing method of flexible double-side printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture within a short time and with high yield a double-side metal laminated film, as an insulation film, which secures adhesion with a copper coating layer even with thickness equal to or less than 20 μm, and has high insulation reliability without creasing the insulation film.SOLUTION: A manufacturing method successively executes: a dehydration processing step of implementing dehydration processing by irradiating at least one surface 1a of an insulation film 1 with ion beams within a vacuum atmosphere and for exhausting generated water vapor; a first surface processing step of implementing surface processing by irradiating the one surface 1a of the insulation film 1 with ion beams; a second surface processing step of implementing surface processing by irradiating another surface 1b with ion beams; a first dry deposition step of successively depositing a base metal layer 2b and a copper membrane layer 3b forming a portion of or all the copper coating layer on any surface of the insulation film 1 according to a dry plating method; and a second dry deposition step of successively depositing a copper membrane layer 3a similarly on the surface where the copper membrane layer 3b has not been deposited.

Description

  The present invention relates to a method and an apparatus for producing a double-sided metal laminate film, which is used in a flexible double-sided printed wiring board and has a copper coating layer formed on both sides of an insulating film without using an adhesive. Moreover, this invention relates to the manufacturing method of the flexible double-sided printed wiring board using this double-sided metal laminated film.

  In recent years, electronic devices typified by mobile devices such as mobile phones and tablet terminals have been rapidly reduced in size, thickness and weight, and parts can be stored in a small space for the materials used for these devices. There is a demand for high-density, high-performance materials that enable it. A flexible double-sided printed wiring board having bending resistance is widely used as a material that meets such requirements.

  However, a flexible double-sided printed wiring board used for a movable portion of a small mobile device that requires high density is required to have a further narrower pitch and better flexibility. In the structure of the flexible double-sided printed wiring board so far, there is a problem that, when it is multilayered or applied to a portion where the bending radius is smaller, disconnection occurs after long-term use. In order to achieve higher bending resistance, it is required to further thin the flexible double-sided printed wiring board.

  The material of the flexible double-sided printed circuit board is a three-layer metal laminated film in which a copper foil as a conductor layer is bonded to an insulating film using an adhesive, and dry plating without using an adhesive on the insulating film. There is a two-layer metal laminated film in which a copper coating layer that becomes a conductor layer is directly formed by a method or a wet plating method.

  In the structure of the three-layer metal laminated film, when etching to obtain a desired wiring pattern, side etching occurs in which etching proceeds not only in the direction perpendicular to the substrate surface but also in the plane direction (side wall surface). The cross-sectional shape of the part tends to be a trapezoid with a wide base, and it is difficult to narrow the wiring pattern. This structure also has a problem that it is difficult to thin the conductor layer.

For this reason, it has become mainstream to apply the structure of the two-layer metal laminated film without such a problem. However, in the structure of this two-layer metal laminated film, the adhesion strength between the insulating film and the copper coating layer is such that a brittle layer such as copper oxide (II) (CuO) or copper oxide (I) (Cu ₂ O) is present at the interface. When it is formed, it is significantly reduced. Therefore, in order to maintain the adhesive strength required for flexible double-sided printed wiring boards, an alloy layer (underlying metal layer) made of nickel, chromium, or the like is formed by dry plating between the insulating film and the copper coating layer. Is done.

  For example, in Japanese Patent Application Laid-Open No. 8-139448, before forming a copper coating layer by electroplating, a dry plating process such as a vacuum deposition method, a sputtering method, or an ion plating method is used to form chromium, chromium oxide, After a base metal layer made of a metal other than copper such as nickel is formed to a thickness of about 50 to 200 mm, a thin copper layer by a dry plating method and an electroless copper plating film by electroless plating are sequentially formed. Yes.

  Japanese Patent Laid-Open No. 6-120630 discloses a nickel method by sputtering from the viewpoint of enabling formation of a fine wiring pattern with a single etching solution while maintaining the adhesion between the insulating film substrate and the copper layer. It is shown that a base metal layer made of a nickel-chromium alloy having a content of 5 at% to 80 at% is formed.

On the other hand, the wiring pattern of the flexible double-sided printed wiring board is generally performed by a chemical etching process such as a subtractive method. The chemical etching process includes an etching process by chemical etching and a water washing process for removing the etching solution. Examples of the etchant corresponding to the chemical etching of the copper coating layer include ferric chloride (FeCl ₃ .2H ₂ O) aqueous solution and cupric chloride (CuCl ₂ .2H ₂ O) aqueous solution.

  However, if the insulating film is not sufficiently dehydrated before the dry plating process, moisture is taken into the underlying metal layer and oxidized, and sufficient chemical etching process cannot be performed. For this reason, the underlying metal layer remains undissolved between the edges of the conductor wiring and between the conductor wiring, and the insulation reliability of the resulting flexible double-sided printed wiring board is reduced due to the remaining metal component called etching residue. There is. Further, there is a problem that the adhesion strength with the insulating film is lowered due to the oxidation of the base metal layer, and the anchor effect by the base metal layer cannot be sufficiently obtained.

  Regarding the dehydration treatment, in Japanese Patent No. 4605454, a heating device such as a heater is used to heat the insulating film to 20 ° C. to 140 ° C. in a vacuum or 100 ° C. to 140 ° C. in the air to perform dehydration. A method is described in which a base metal layer is formed by dry plating after the treatment. According to this method, since the insulating film can be sufficiently dehydrated, generation of etching residues is prevented. However, there is a problem in productivity because dehydration takes a long time at a temperature of 140 ° C. or lower. In addition, the insulating film may be wrinkled by a thermal load. To avoid this, an insulating film having a sufficient thickness must be used, and the flexible double-sided printed wiring board is thin. It will be difficult to satisfy the demands for conversion.

  In contrast, JP 2011-20345 A discloses that water or various organic solvents in a resin film can be obtained by performing plasma treatment or ion beam treatment on at least one surface of an insulating film under a reduced pressure atmosphere. It is described that can be removed. However, in this dehydration process, since the insulating film after processing becomes a high temperature of 200 ° C. or higher, it is necessary to cool the insulating film after processing.

  On the other hand, regarding improvement of the anchor effect, JP-A-5-251843 discloses that the polyimide film is used for glow discharge of a gas containing nitrogen oxide for the purpose of modifying the surface properties of the polyimide film which is an insulating film. It is disclosed that a base metal layer is continuously formed by an ultra-thin film of a nickel-copper alloy while maintaining a vacuum state after exposure for a short time. However, in the surface treatment of the insulating film by glow discharge, the anchor effect by the base metal layer is not sufficiently obtained.

It is known that a plasma treatment method, an ion beam treatment method, or the like is applied also to the surface treatment of the insulating film. For example, Japanese Patent Application Laid-Open No. 2006-49893 discloses an ion beam processing method in which an ion beam is irradiated using an oxygen (O ₂ ) -argon (Ar) mixed gas. As described above, when the ion beam treatment method is used for the surface treatment of the insulating film, the adhesion between the insulating film and the base metal layer can be improved.

  When a double-sided metal laminated film is manufactured by applying such a double-layered metal laminated film structure, as disclosed in JP-A-5-251843, one surface of the insulating film is modified to form a base metal. Usually, after forming a layer and forming a copper thin film thereon, the other surface of the insulating film is modified to form a base metal layer, and a copper thin film is formed thereon.

Japanese Patent Laid-Open No. 8-139448 JP-A-6-120630 Japanese Patent No. 4605454 JP 2011-20345 A JP-A-5-251843 JP 2006-49893 A

  However, in the production of double-sided metal laminated film, it is possible to sufficiently suppress the generation of wrinkles on the surface of the insulating film even when a plasma treatment or an ion beam treatment method is employed as the dehydration treatment and surface treatment of the insulation film. Have difficulty. In particular, in order to further reduce the thickness of the flexible double-sided printed wiring board, when using an insulating film having a thickness of 20 μm or less, this tendency becomes prominent and the yield of the flexible double-sided printed wiring board decreases. It has become.

  In view of this problem, in the production of a double-sided metal laminated film, the present invention forms a base metal layer on both surfaces of an insulating film and forms a copper coating layer on both sides of the base metal layer. Provided is a method for producing a double-sided metal laminated film having high insulation reliability in a short time and in a high yield without sufficiently wrinkling the insulating film while ensuring sufficient adhesion between the film and the copper coating layer. For the purpose.

  In view of such circumstances, as a result of intensive studies by the present inventors, after forming a base metal layer on both surfaces of the insulating film by a dry plating method, a copper coating layer is formed on the surface of the base metal layer. In the method for producing a double-sided metal laminated film, dehydration treatment is performed by irradiating at least one surface of the insulation film with an ion beam, water vapor generated by the dehydration treatment is appropriately exhausted, and the insulation film After the surface treatment on both sides of the insulating film is performed by sequentially irradiating both sides of the surface of the insulating film, the base metal layer and the copper thin film layer are sequentially formed on both sides of the insulating film. Even when a film with a thickness of 20 μm or less is used, a flexible double-sided pre-wrinkle that does not wrinkle and has sufficient adhesion The door wiring board to obtain a knowledge that can be obtained in a short time. The present invention has been made based on this finding.

That is, in the method for producing a double-sided metal laminated film of the present invention, a base metal layer is formed by a dry plating method on both sides of an insulating film without using an adhesive, and then a copper film layer is formed on the surface of the base metal layer. When doing
Dehydration by irradiating at least one surface of the insulating film with an ion beam in a vacuum atmosphere, dehydrating while suppressing the temperature rise to 90 ° C. or less, and exhausting water vapor generated by the dehydration Processing steps;
A first surface treatment step of performing surface treatment by irradiating one surface of the insulating film with an ion beam;
A second surface treatment step of irradiating the other surface of the insulating film with an ion beam for surface treatment;
A first dry composition in which the base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on any surface of the surface-treated insulating film by a dry plating method. A membrane process;
First, the base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on the surface of the insulating film on which the copper thin film layer is not formed by dry plating. And 2 dry film forming step.

  The dehydration process and the first surface treatment process are preferably performed simultaneously.

The ion beam irradiation is preferably performed using an ion gas comprising argon, nitrogen, oxygen, or a mixed gas of at least two selected from these groups, and the first surface treatment step and the second surface treatment. The degree of vacuum in the process is preferably 1 × 10 ⁻⁴ Pa to 1 Pa.

The dehydration step, the flow rate of the ion gas in the first surface treatment step and the second surface treatment step, 1 atm, at 25 ° C. Conversion is preferably 40cm ³ / min~80cm ³ / min.

Moreover, the double-sided metal laminated film manufacturing apparatus of the present invention comprises a vacuum chamber and a roll-to-roll film processing apparatus disposed in the vacuum chamber,
The roll-to-roll film processing apparatus includes an unwinding roll, a winding roll, and a film track between these rolls,
A dehydrating ion gun for irradiating at least one surface of the insulating film with an ion beam to dehydrate the insulating film;
An exhaust device for exhausting water vapor generated by the dehydration treatment;
A first surface treatment ion gun that performs surface treatment by irradiating one surface of the insulating film with an ion beam;
On the downstream side of the first surface treatment ion gun, disposed on the opposite side of the first surface treatment ion gun across the track of the insulation film, and irradiating the other surface of the insulation film with an ion beam to perform surface treatment. A second surface treatment ion gun;
A base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on any surface of the insulating film disposed on the downstream side of the second surface treatment ion gun and subjected to the surface treatment. A first dry film forming apparatus for forming a film;
On the downstream side of the first dry film forming apparatus, on the opposite side of the first dry film forming apparatus across the track of the insulating film, on the surface of the insulating film on which the copper thin film layer is not formed A second dry film forming apparatus for sequentially forming a copper thin film layer constituting part or all of the base metal layer and the copper coating layer;
It is characterized by providing.

In particular, the double-sided metal laminated film manufacturing apparatus of the present invention includes a vacuum chamber and a roll-to-roll film processing apparatus disposed in the vacuum chamber,
The roll-to-roll film processing apparatus includes an unwinding roll, a winding roll, and a film track between these rolls,
A first surface treatment ion gun for performing dehydration treatment and surface treatment by irradiating one surface of the insulating film with an ion beam;
An exhaust device for exhausting water vapor generated by the dehydration process downstream of the first surface treatment ion gun;
A second surface treatment ion gun disposed on the opposite side of the first surface treatment ion gun across the track of the insulation film on the downstream side of the exhaust device and irradiating the other surface of the insulation film with an ion beam;
A base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on any surface of the insulating film disposed on the downstream side of the second surface treatment ion gun and subjected to the surface treatment. A first dry film forming apparatus for forming a film;
On the downstream side of the first dry film forming apparatus, on the opposite side of the first dry film forming apparatus across the track of the insulating film, on the surface of the insulating film on which the copper thin film layer is not formed A second dry film forming apparatus for sequentially forming a copper thin film layer constituting part or all of the base metal layer and the copper coating layer;
It is characterized by providing.

  According to the manufacturing method of the present invention, even when an insulating film having a thickness of 20 μm or less is used, sufficient adhesion between the insulating film and the copper coating layer is ensured, and the insulating film is wrinkled. The double-sided metal laminated film having high insulation reliability can be produced in a short time and without yield.

  Moreover, about the double-sided metal laminated film obtained by this invention, it is possible to obtain a flexible double-sided printed wiring board by the wiring process by a subtractive method or a semiadditive method. Such a flexible double-sided printed wiring board having a small thickness and excellent bending resistance is suitably applied to a movable part such as a small-sized mobile device that has a high demand for high density.

FIG. 1 is a flowchart showing an embodiment of the present invention. FIG. 2 is a flow diagram illustrating another embodiment of the present invention. FIG. 3 is a schematic view of a continuous sputtering apparatus for carrying out the method for producing a double-sided metal laminated film of the present invention.

1. Method for producing double-sided metal laminated film The method for producing a double-sided metal laminated film according to the present invention comprises forming a base metal layer made of a nickel alloy by dry plating without using an adhesive on both sides of an insulating film, It is a manufacturing method of the double-sided metal laminated film which forms a copper coating layer on the surface of a layer.

  In particular, the method for producing a double-sided metal laminated film of the present invention irradiates at least one surface (1a, 1b) of an insulating film (1) with an ion beam in a vacuum atmosphere as shown in FIG. In the same manner as the dehydration process of exhausting the water vapor generated by the dehydration process while suppressing the temperature rise of 90 ° C. or less, the surface of one of the insulating films (1a) is irradiated with an ion beam, One of a first surface treatment step for performing a surface treatment, a second surface treatment step for irradiating the other surface (1b) of the insulating film with an ion beam to perform the surface treatment, and an insulating film subjected to the surface treatment. A first dry film forming step of sequentially forming the base metal layer (2b) and a copper thin film layer (3b) constituting a part or all of the copper coating layer on the surface of the substrate by dry plating; Insulation fill A copper thin film layer (3a) constituting part or all of the base metal layer (2a) and the copper coating layer by dry plating on the surface (1a) on which the copper thin film layer is not formed; A second dry film forming step of sequentially forming films.

  In addition, in the manufacturing method of the double-sided metal laminated film of this invention, after performing surface treatment by irradiation of an ion beam to the surface (1a, 1b) of both sides of an insulating film (1), a base metal layer (2a, 2b) and The copper thin film layers (3a, 3b) may be formed, and the order of the surfaces on which the films are formed is not limited. That is, the film may be formed in the order as shown in FIG. 1, or the surface of both sides (1a, 1b) of the insulating film (1) is subjected to surface treatment by irradiation with an ion beam, and then the insulating film is formed. After a base metal layer (2a) and a copper thin film layer (3a) are formed on one surface (1a) of the insulating film by dry plating, the base metal is formed on the other surface (1b) of the insulating film by dry plating. The layer (2a) and the copper thin film layer (3a) may be formed.

(Insulating film)
The insulating film that can be used in the method for producing a double-sided metal laminate film of the present invention can be used without particular limitation as long as it is an insulating film that is used in the production of a general flexible circuit board. . Preferably, polyimide film, polyamide film, polyester film such as polyethylene terephthalate (PET) or polyethylene terephthalate (PEN), polytetrafluoroethylene film, polyphenylene sulfide film, polyethylene naphthalate film, liquid crystal polymer film One insulating film selected from the group of films is used.

  In particular, considering the heat resistance, dielectric properties, electrical insulation, flexible double-sided printed wiring board manufacturing process and chemical resistance in the next process, etc. required for flexible double-sided printed wiring board It is more preferable to select appropriately.

  As such an insulating film, specifically, polyimide films include Kapton (registered trademark) manufactured by Toray DuPont Co., Ltd., Upilex (registered trademark) manufactured by Ube Industries, Ltd., Apical manufactured by Kaneka Corporation ( Registered trademark), XENO (registered trademark) manufactured by Toyobo Co., Ltd., and the like. Examples of the aramid film that is an aromatic polyamide film include Mikutron (registered trademark) manufactured by Toray Industries, Inc., and Aramica (registered trademark) manufactured by Teijin Advanced Film Co., Ltd.

  In addition, the effect mentioned above is acquired also in manufacture of the double-sided metal laminated film using the thing whose thickness is 40 micrometers or less conventionally used as an insulating film as this invention. However, in the present invention, particularly in the production of a double-sided metal laminated film using an insulating film having a thickness of 20 μm or less, and further 15 μm or less, which is thinner than conventional ones, the surface of the insulating film caused by the surface treatment is wrinkled. Can be prevented, and in the obtained double-sided metal laminated film, high adhesion between the insulating film and the copper coating layer as the conductor layer can be achieved.

(Processing method)
The manufacturing method of the double-sided metal laminated film of the present invention is a process in which an insulating film wound in a roll shape is conveyed while being conveyed in a roll-to-roll method when individually processing the insulating film cut into a predetermined size. It is applicable to any of the cases. In addition, the roll-to-roll method is a plurality of rollers for holding an insulating film between an unwinding roll that installs an insulating film wound in a roll shape, and a winding roll that winds the insulating film. In this method, various processing units are arranged as appropriate and processing is performed continuously. By performing the production method of the double-sided metal laminated film of the present invention by a roll-to-roll method, the double-sided metal laminated film can be obtained efficiently in a shorter time.

  Hereinafter, the manufacturing method of a double-sided metal laminated film is demonstrated in detail for every process to this invention.

(1) Dehydration process In the dehydration process of the present invention, at least one surface of the insulating film is subjected to ion beam treatment in a vacuum atmosphere, thereby dehydrating and exhausting water vapor generated by the dehydration. Thus, a dehydration process is performed.

  As the dehydration treatment of the insulating film, plasma treatment, ion beam treatment, and the like are known. Among these, ion beam processing is different from plasma processing in that directivity is high, only ions are emitted, and the energy density of the irradiated part is high. That is, in the plasma treatment, since the insulating film passes through the plasma atmosphere when the insulating film is dehydrated, there is a possibility that the insulating film is damaged by the plasma and the film strength is lowered. is there. On the other hand, in the ion beam treatment, since the insulating film does not pass through the plasma at the ion beam generation site, such a problem does not occur.

  Moreover, plasma processing requires time for processing, and is not suitable for continuous processing using a roll-to-roll film processing apparatus described later. In contrast, in ion beam processing, the gas released from the ion gun is accelerated, and at the same time, a voltage is applied to the insulating film to be dehydrated, and the attractive force is generated between the ions generated from the ion gun and the insulating film. Charge deformation is performed by the action of (attraction force) or repulsive force. For this reason, since dehydration in a vacuum atmosphere is promoted, dehydration in a short time becomes possible. For these reasons, in the present invention, ion beam treatment is employed as the dehydration treatment of the insulating film.

  Note that it is sufficient that the ion beam treatment is performed on at least one of the surfaces of the insulating film. This is because the dehydration process by the ion beam process does not directly heat the insulating film as described above but utilizes the effect of charge deformation. However, ion beam treatment may be performed on both surfaces of the insulating film from the viewpoint of performing dehydration treatment more reliably.

  As the ion beam treatment, an ion implantation method (ion implantation) in which ionized atoms or molecules collide with the insulating film in a state accelerated by high energy of several tens keV to several MeV, and these ions enter the insulating film, In addition, an ion beam irradiation method (ionirradiation) in which a concavo-convex surface is formed on the surface of the insulating film can be mentioned, and any of them can be applied in the present invention.

  In addition, when the insulating film is dehydrated by ion beam treatment, various conditions as described later are appropriately controlled in order to prevent the generation of wrinkles due to the heat load on the insulating film and enable the dehydrating process in a short time. It is necessary to do.

(Ion gas)
In the dehydration treatment by ion beam irradiation of the present invention, the gas released from the ion gun is selected from argon (Ar), oxygen (O ₂ ), nitrogen (N ₂ ), or these groups from the viewpoint of production cost. In particular, argon (Ar) is preferably used from the viewpoint of preventing gas contamination.

Flow rate of the ion gas is 1 atm, at 25 ° C. terms, preferably 40cm ³ / min~80cm ³ / min, more preferably from 50cm ³ / min~70cm ³ / min. If the flow rate of the ion gas is less than 40 cm ³ / min in terms of 1 atm and 25 ° C., there may be a problem that the discharge is not performed or the discharge state becomes unstable. On the other hand, if it exceeds 80 cm ³ / min, the discharge state becomes unstable, and there is a possibility that a problem that stable treatment cannot be performed arises.

(Degree of vacuum)
The dehydration process is performed in a vacuum atmosphere, and the degree of vacuum at this time is 1 Pa or less, preferably 1 × 10 ⁻⁴ Pa to 1 Pa, more preferably 2 × 10 ⁻⁴ Pa to 0.8 Pa. is necessary. When the degree of vacuum exceeds 1 Pa, the ionized gas concentration is relatively reduced, and not only the effect of the above-described charge deformation cannot be sufficiently obtained, but also the drying effect by vacuum is reduced, so that the drying time becomes longer. End up. The lower limit of the degree of vacuum is not particularly limited. However, if a high degree of vacuum is obtained, the production cost increases, and the time until the desired degree of vacuum is reached increases. Sex is reduced. For this reason, about 1 × 10 ⁻⁴ Pa is practically the lower limit.

(Irradiation conditions)
In the dehydration process of the present invention, it is necessary to suppress the temperature rise of the insulating film accompanying the dehydration process to 90 ° C. or less, preferably 80 ° C. or less, more preferably 70 ° C. or less. If the temperature rise due to the dehydration process exceeds 90 ° C., even if the insulating film is subsequently cooled, it is impossible to prevent the generation of wrinkles due to heat load, or it takes a long time for cooling. Therefore, it is difficult to shorten the processing time. In addition, also in the 1st surface treatment process and 2nd surface treatment process which are mentioned later, it is preferable to suppress the temperature rise of an insulating film to the said range.

Thus, in order to suppress the temperature rise accompanying the dehydration process, it is necessary to appropriately manage the ion beam irradiation conditions. The ion beam irradiation conditions should be appropriately set according to the apparatus to be used, and are not particularly limited. However, the ion gun discharge voltage, discharge current, discharge power, beam gas flow rate, ion gun chamber pressure, film By selecting the feed speed of the ion particle, the energy of the ion particles is preferably set to 1 × 10 ⁻³ keV to 1 keV. Further, it is preferable to set the dose and ^{10 12 ions / cm 2 ~10 16} ions / cm 2.

When the energy of the ion particles is less than 1 × 10 ⁻³ keV or when the irradiation amount is less than 10 ¹² ions / m ² , the moisture inside the insulating film may not be sufficiently dehydrated. On the other hand, when the energy of the ion particles exceeds 1 keV, or when the irradiation amount exceeds 1 × 10 ¹⁶ ions / cm ² , not only wrinkles are generated due to the temperature rise associated with the dehydration process, but also the insulation. Since damage to the film increases, there is a risk that the strength of the insulating film is reduced and further, there is a problem of breakage.

  The treatment time with the ion beam should be appropriately adjusted depending on the thickness of the insulating film, etc., but preferably 3 seconds to 60 seconds, more preferably 5 seconds to 40 seconds under the irradiation conditions. It is enough. If the treatment time is less than 3 seconds, the moisture inside the insulating film may not be sufficiently dehydrated. On the other hand, if it exceeds 60 seconds, the damage received by the insulating film increases.

  In addition, depending on various conditions such as the output of the ion gun that performs dehydration treatment by ion beam irradiation, differences in the ion gun equipment, gas pressure of the ion gun, thickness and width of the insulating film, and transport speed, appropriate processing conditions for the insulating film Is different. For this reason, it is necessary to select appropriate processing conditions in consideration of the characteristics required for the obtained double-sided metal laminated film and the thermal load on the insulating film by ion beam processing. It is preferable to select after conducting a preliminary test.

(Vapor exhaust)
If the water vapor generated by the dehydration process is not properly exhausted, the degree of vacuum decreases due to an increase in water pressure, and etching residue may be generated due to the water vapor flowing into the sputtering zone. is there. For this reason, the water vapor generated by the dehydration treatment is exhausted, and the degree of vacuum is maintained at 1 Pa or less, preferably 1 × 10 ⁻⁴ Pa to 1 Pa, more preferably 2 × 10 ⁻⁴ Pa to 0.8 Pa. It is necessary to control the water pressure at that time to 0.8 Pa or less, preferably 8 × 10 ⁻³ Pa to 0.8 Pa. In actual operation, if the degree of vacuum can be reduced to 1 Pa or less, the water pressure at this time can be reduced to 0.8 Pa or less. Therefore, the water vapor can be exhausted based on the degree of vacuum. preferable.

  A method for exhausting water vapor is not particularly limited, and a known technique such as a cryopump, a cryocoil, a turbo molecular pump, or the like can be used.

(Cooling system)
In the present invention, by following the above conditions, it is possible to suppress the temperature rise of the insulating film due to the ion beam treatment, but depending on the thickness of the insulating film and the combination of the energy or irradiation amount of ion particles and the irradiation time. The temperature of the insulating film may rise to about 90 ° C. For this reason, it is preferable to cool an insulating film after a dehydration process and to suppress the temperature rise of an insulating film. The cooling means is not particularly limited, and for example, known means such as a cooling roll can be employed.

  In particular, in the present invention, in addition to the dehydration process, the ion beam process is also performed in the surface treatment process to be described later, so the temperature rise of the insulation film after the second surface treatment process is suppressed relative to the insulation film before the dehydration process. It is preferable to dispose the cooling means, and it is more preferable to dispose the cooling means so as to suppress the temperature rise before and after each step. By providing such a cooling means, it is preferable that the temperature rise of an insulating film shall be 50 degrees C or less, and it is more preferable to set it as 30 degrees C or less. When the temperature rise exceeds 50 ° C., the heat load of the insulating film increases, and it may be impossible to prevent the generation of wrinkles. In addition, the time required for cooling the insulating film becomes longer, which may hinder productivity.

  In addition, the temperature rise of an insulating film can be calculated | required by measuring the temperature of the insulating film before and behind each process using a radiation thermometer etc.

(2) Surface treatment step After the dehydration step, the surface treatment step irradiates one surface of the insulating film with an ion beam to perform surface treatment (first surface treatment step), and then on the other surface of the insulating film. This is a step of performing surface treatment (second surface treatment step) by irradiating with an ion beam (see FIG. 1), thereby modifying the surface of the insulating film and improving the adhesion to the underlying metal layer. .

  As in the conventional method for producing a double-sided metal laminated film described in JP-A-5-251843, the surface treatment and the formation of a base metal layer and a copper thin film layer on one surface of an insulating film After performing the surface treatment and film formation of the base metal layer and the copper thin film layer on the other surface of the insulating film, when performing the surface treatment and film formation on the other surface, The mechanical load due to the surface treatment is not relieved, and there is a possibility that problems such as wrinkles occur on the surface. Such a tendency starts to appear when an insulating film having a thickness of 40 μm or less is used, and becomes particularly prominent when a film having a thickness of 20 μm or less is used.

  On the other hand, in this invention, after surface-treating with respect to the surface of the both sides of an insulating film, the base metal layer and the copper thin film layer are formed into each of the surface after these surface treatments. For this reason, the mechanical load due to the irradiation of the ion beam is relieved, and even when an insulating film having a thickness of 20 μm or less is used, the generation of wrinkles can be prevented and sufficient adhesion can be achieved. The double-sided metal laminate film can be obtained.

  In the embodiment shown in FIG. 1, the dehydration process and the first surface treatment process described above are separate processes, but the ion beam irradiation conditions in the dehydration process or the first surface treatment process are adjusted. Thus, these steps can be performed simultaneously (see FIG. 2).

  The surface treatment by ion beam treatment uses charge deformation by ion beam irradiation, as in the case of dehydration treatment. That is, due to charge deformation caused by ion beam irradiation, the chemical bonding state of molecules on the surface of the insulating film changes, and due to the high directivity of the ion beam, a fresh interface is formed on the insulating film due to ion collision. Appears, and high adhesion is realized between the insulating film and the underlying metal layer.

  Since the ion gas species used for the ion beam treatment in the surface treatment step and the flow rate thereof, the degree of vacuum required, and further the temperature rise are basically the same as the dehydration step, The description here is omitted, and the ion beam irradiation conditions for surface treatment will be described below.

In the surface treatment process, as described above, the chemical bond state of the insulating film is changed, and in order to form a fresh interface, it is necessary to increase the energy of ion particles compared to the case of the dehydration process. is there. Specifically, the energy of the ion particles is preferably 5 × 10 ⁻² keV to 1 keV. On the other hand, it is sufficient that the irradiation amount is approximately the same as that in the dehydration process, and specifically, it is preferably 10 ¹² ions / cm ² to 10 ¹⁶ ions / cm ² . When the energy of the ion particles is less than 5 × 10 ⁻² keV, or when the irradiation amount is less than 10 ¹² ions / cm ² , the effect of the surface treatment may not be sufficiently obtained. On the other hand, when the energy of the ion particles exceeds 1 keV, or when the irradiation amount exceeds 1 × 10 ¹⁶ ions / cm ² , not only wrinkles are generated due to the temperature rise associated with the dehydration process, but also the insulation. Since damage to the film increases, there is a risk that the strength of the insulating film is reduced and further, there is a problem of breakage.

  The treatment time with the ion beam should be appropriately adjusted depending on the thickness of the insulating film, etc., but preferably 1 second to 30 seconds, more preferably 3 seconds to 20 seconds under the irradiation conditions. It is enough. If the treatment time is less than 1 second, the effect of the surface treatment may not be sufficiently obtained. Moreover, if it exceeds 30 seconds, the damage which an insulating film receives will become large.

Further, as in the embodiment shown in FIG. 2, when the dehydration process and the first surface treatment process are performed simultaneously, the energy of the ion particles is preferably 1 × 10 ⁻² keV to 1 keV. On the other hand, it is sufficient that the irradiation amount is similar to that in the dehydration process, and specifically, it is preferably 10 ¹² ions / cm ² to 10 ¹⁶ ions / cm ² . When the energy of the ion particles is less than 1 × 10 ⁻² keV, or when the irradiation amount is less than 10 ¹² ions / cm ² , the effect of the surface treatment may not be sufficiently obtained. On the other hand, when the energy of the ion particles exceeds 1 keV, or when the irradiation amount exceeds 1 × 10 ¹⁶ ions / cm ² , not only wrinkles are generated due to the temperature rise associated with the dehydration process, but also the insulation. Since damage to the film increases, there is a risk that the strength of the insulating film is reduced and further, there is a problem of breakage.

  The treatment time with the ion beam should be appropriately adjusted depending on the thickness of the insulating film, etc., but preferably 3 seconds to 60 seconds, more preferably 5 seconds to 40 seconds under the irradiation conditions. It is enough. If the treatment time is less than 3 seconds, the effect of the surface treatment may not be sufficiently obtained. Moreover, if it exceeds 60 seconds, the damage which an insulating film receives will become large.

  As described above, in the surface treatment process, considering the thickness of the insulation film, the characteristics required for the obtained double-sided metal laminated film, the heat load on the insulation film by ion beam treatment, etc., appropriate treatment conditions are set. It is necessary to select, and it is preferable to select such processing conditions after conducting a preliminary test.

(3) Dry film forming process The dry film forming process is performed by subjecting the surfaces (1a, 1b) on both sides of the insulating film (1) to surface treatment by irradiation with an ion beam, followed by dry plating to form a base metal layer (2a 2b) and copper thin film layers (3a, 3b).

(Dry plating method)
As the dry plating method, a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, and the like can be used. From the viewpoint of ease of handling, productivity, and cost, the base metal layer and It is preferable to form a copper thin film layer.

  The sputtering conditions when the sputtering method is employed are appropriately selected. For example, a polyimide resin having a thickness of 10 μm to 20 μm is used as the insulating film, and a nickel alloy having a thickness of about 0.01 μm to 10 μm is used. In the case where the underlying metal layer and the copper thin film layer are continuously formed, it is preferable to form the film at an ultimate vacuum of 0.1 Pa or less and a sputtering gas pressure of 0.5 Pa to 5.0 Pa. Note that other conditions such as input power vary depending on the type, size, or target film thickness of the target, and therefore it is preferable to select them appropriately after conducting a preliminary test or the like. The sputtering conditions are the same in the first dry film forming process and the second dry film forming process.

(Underlying metal layer)
The base metal layer contributes to improvement in adhesion between the insulating film and the copper coating layer and insulation reliability of the flexible double-sided printed wiring board. As such a base metal layer, it is preferable to use a nickel-based alloy. In particular, from the viewpoint of improving the corrosion resistance of the base metal layer, it is preferable to use a nickel alloy to which one or more elements selected from chromium, vanadium, titanium, molybdenum, cobalt, and tungsten are added. Among these, a nickel-chromium alloy is preferable, and the chromium content is more preferably 15% by mass to 25% by mass, and further preferably 15% by mass to 22% by mass. Such a nickel-chromium alloy has high insulation reliability and can easily form a wiring pattern.

  The thickness of the underlying metal layer is appropriately selected from the type and composition of the metal or alloy forming the underlying metal layer, the flexible double-sided printed wiring board and the workability of the wiring, the adhesion required for the wiring, and the insulation reliability. However, in the present invention, it is preferably 3 nm to 50 nm, more preferably 5 nm to 40 nm, and even more preferably 7 nm to 30 nm. When the thickness of the underlying metal layer is less than 3 nm, when the metal layer other than the wiring portion is removed by flash etching or the like and the wiring pattern is formed, the etching solution erodes the metal layer, and between the insulating film and the metal layer. There is a case where the wiring penetrates and the wiring rises. On the other hand, if the thickness of the underlying metal layer exceeds 50 nm, when the wiring is finally produced by flash etching or the like, the metal layer may remain without being completely removed, resulting in an insulation failure between the wirings. .

(Copper thin film layer)
The copper thin film layer constitutes part or all of the copper coating layer that becomes the wiring of the flexible double-sided printed wiring board by wiring processing. The copper thin film layer is formed on the surface by a dry plating method such as a sputtering method after the base metal layer is formed.

  The thickness of the copper thin film layer is preferably 0.01 μm to 1 μm, more preferably 0.03 μm to 0.7 μm, and still more preferably 0.05 μm to 0.35 μm. When the thickness of the copper thin film layer is less than 0.01 μm, a problem may easily occur in the electrical conductivity of the wiring portion, or a problem in strength may occur. On the other hand, since the film formation rate by the dry plating method is slower than the film formation rate by the electroplating method, if the film formation exceeds 1 μm by the dry plating method, the productivity is lowered.

(4) Wet film formation process The film thickness of the copper coating layer of the double-sided metal laminate film is determined by the choice of the wiring method of the flexible double-sided printed wiring board, that is, the subtractive method or the semi-additive method. is there. When a wiring pattern is formed by the semi-additive method, a copper film layer thickness of about 1 μm is sufficient. Therefore, even if the copper film layer is formed only by a dry film forming process, productivity is deteriorated. Does not occur. However, when a wiring pattern is formed by a subtractive method, a copper coating layer having a film thickness exceeding 1 μm may be required. In such a case, the copper coating layer is formed only by a dry film forming process. It is conceivable that the productivity is remarkably reduced due to the film formation rate when it is formed. For this reason, when it is going to form a copper film layer exceeding 1 micrometer on the surface of a base metal layer, it is preferable to further provide a wet film-forming process, and such wet film-forming can be performed by an electroplating method. More preferred.

  The film thickness of the copper coating layer is preferably in the range of 0.01 μm to 35 μm, more preferably in the range of 0.3 μm to 15 μm, and even more preferably in the range of 0.3 μm to 12 μm. If the film thickness of the copper coating layer is less than 0.01 μm, a problem may easily occur in the electrical conductivity of the wiring portion, and a problem in strength may occur. On the other hand, when the film thickness exceeds 35 μm, hair cracks, warpage, and the like may occur and adhesion may be reduced, and the influence of side etching may be increased, and narrowing the pitch may be difficult. In addition, it does not specifically limit as an electroplating method, For example, a well-known electroplating method can be used in copper sulfate aqueous solution.

2. In the present invention, the first surface treatment step and the second surface treatment step are performed by a roll-to-roll film processing apparatus provided with an ion gun that can irradiate the insulating film from one direction. It is preferable. Furthermore, in the present invention, in the continuous sputtering apparatus provided with the sputtering apparatus, all of the dehydration process, the first surface treatment process, the second surface treatment process, the first dry film formation process, and the second dry film formation process are continuously performed. It is preferable to be able to do this.

  As an example for carrying out such a manufacturing method of the present invention, particularly the embodiment shown in FIG. 1, a schematic view of a continuous sputtering apparatus (4) is shown in FIG. The continuous sputtering apparatus (4) includes a vacuum chamber (5) and a roll-to-roll film processing apparatus disposed in the vacuum chamber (5). This roll-to-roll film device comprises an unwinding roll (6), a winding roll (7), and a film track between these rolls.

  This roll-to-roll film processing apparatus includes a dehydrating ion gun (8) for dehydrating the insulating film (1) between the unwinding roll (6) and the winding roll (7), and a dehydrating process. A first surface treatment ion gun (9a) disposed on the downstream side of the ion gun (8) and irradiating one surface of the insulating film (1) with an ion beam, and a film on the downstream side of the first surface treatment ion gun (9a) A second surface treatment ion gun (9b) disposed on the opposite side of the first surface treatment ion gun (9a) across the orbit and irradiating the other surface of the insulating film (1) with an ion beam; and a second surface treatment ion gun A base metal layer (2b) and a copper thin film layer (3b) are sequentially formed on any surface of the insulating film (1) disposed on the downstream side of (9b) and subjected to surface treatment. Dry deposition equipment (70) and a copper thin film layer of the insulating film (1) disposed downstream of the first dry film forming apparatus (70) and on the opposite side of the first dry film forming apparatus (70) across the film track. At least a second dry deposition apparatus (71) for sequentially depositing the base metal layer (2a) and the copper thin film layer (3a) on the surface on which no film is formed.

  The insulating film (1) unwound from the unwinding roll (6) is conveyed before the dehydration ion gun (8) through the guide roll (10), and dehydrated by being irradiated with an ion beam. (Dehydration process). The water vapor generated at this time is exhausted out of the vacuum chamber (5) by the exhaust device (25). Thereafter, the insulating film (1) is conveyed in front of the first and second surface-treated ion guns (9a, 9b) via the tension sensor roll (20) and the guide roll (11), and both side surfaces (1a, Surface treatment is performed by irradiating the ion beam with the first and second surface-treated ion guns (9a, 9b) on 1b) (first and second surface treatment steps). In order to keep the temperature rise of the insulating film before the dehydration process and after the first surface treatment process, and before the first surface treatment process and after the second surface treatment process, within 50 ° C., respectively, When the cooling roll is used, for example, between the dehydration ion gun (8) and the first surface treatment ion gun (9a), and between the first surface treatment ion gun (9a) and the second surface treatment ion gun (9b). It is preferable to dispose a cooling roll respectively, and it is more preferable to use a tension sensor roll (20) and a guide roll (11) having a function as a cooling roll.

  As described above, the insulating film (1) is subjected to dehydration treatment on at least one surface (1a or 1b), and then subjected to surface treatment on both side surfaces (1a, 1b), and the guide roll (12) and the feed roll (30). ) To the first dry film forming apparatus (70). In the first dry-type film forming apparatus (70), the base metal layer (2b) and the copper thin film are formed on the cooling can roll (40) by the sputtering method using the sputtering cathode (50, 51) on the surface (1b). The layer (3b) is formed (first dry film forming step).

  Furthermore, it is conveyed to a 2nd dry-type film-forming apparatus (71) through a guide roll (13), a tension sensor roll (21), a guide roll (14-16), and a feed roll (31). In the second dry film forming apparatus (71), the base metal layer (2a) and the copper thin film are formed on the cooling can roll (41) by the sputtering method using the sputtering cathode (60, 61) on the surface (1a). The layer (3a) is formed (second dry film forming step).

  As described above, the insulating film (1) is formed on the both side surfaces (1a, 1b) with the base metal layer (2a, 2b) and the copper thin film layer (3a, 3b), then the guide roll (17), tension It is wound up by a winding roll (7) through a sensor roll (22) and a guide roll (18).

In the continuous sputtering apparatus (4) as shown in FIG. 3, the shape of the vacuum chamber (5) is not limited, but it is necessary to be able to maintain a reduced pressure in the range of 1 × 10 ⁻⁴ Pa to 1 Pa. In addition, as the unwinding roll (6) and the winding roll (7), those capable of maintaining the balance of the tension of the insulating film (1) by torque control using a powder clutch or the like are used. Further, as the cooling can roll (40, 41) and the feed roll (30, 31), those provided with power by a servo motor are used. Further, as the tension sensor roll (21) and the guide rolls (16, 18), those having a function as a drive roll are used.

  A partition is provided between the unwinding roll (6) and the guide roll (10), between the guide roll (12) and the feed roll (30), and between the guide roll (16) and the feed roll (31). The atmosphere in each step is changed by dividing the atmosphere of the discharge roll (6), the first and second surface treatment ion guns (9a, 9b), the sputtering cathode (50, 51), and the sputtering cathode (60, 61). It is also possible.

  In the case of carrying out the embodiment shown in FIG. 2, the dehydration ion gun (8) is omitted, and the continuous sputtering is performed so that the dehydration process and the first surface treatment are performed by the first surface treatment ion gun (9a). What is necessary is just to comprise an apparatus (4). In this case, it is necessary to dispose the exhaust device (25) on the downstream side of the first surface treatment ion gun (9a). Further, even in the continuous sputtering apparatus (4) shown in FIG. 3, only one of the dehydration ion gun (8) and the first surface treatment ion gun (9a) is used, and dehydration is performed by the surface treatment ion gun. The embodiment shown in FIG. 2 can be implemented by performing the treatment and the first surface treatment and disposing the exhaust device downstream of the surface treatment ion gun.

3. Manufacturing method of flexible double-sided printed wiring board A flexible double-sided printed wiring board can be manufactured by wiring a double-sided metal laminate film by a subtractive method or a semi-additive method.

  Since these methods are the same as those in the prior art, detailed description is omitted, but in any method, the base metal layer and the copper coating layer other than the wiring portion are removed by the etching process, so that the insulating film and If the adherent base metal layer is oxidized by moisture contained in the insulating film, the base metal layer cannot be completely removed by the etching process, which may cause poor conduction. Further, the oxidation of the base metal layer may cause a decrease in adhesion with the insulating film. In the present invention, by performing the above-described dehydration process, it is possible to remove the moisture in the insulating film in a short time while suppressing the generation of wrinkles, so that the problem due to the oxidation of the underlying metal layer is solved, Productivity of the flexible double-sided printed wiring board can be improved.

  In addition, since the film thickness of a copper coating layer needs the film thickness equivalent to the film thickness of wiring, when carrying out wiring processing by a subtractive method, as mentioned above, it is further wet after a dry-type film-forming process. A film forming process may be required. On the other hand, in the case of wiring processing by the semi-additive method, the film thickness is only required to ensure the conductivity necessary for electrodeposition, and further, the portion unnecessary for wiring is considered to be removed by soft etching. It is enough. For this reason, there is no problem even if only the dry film forming step, but from the viewpoint of ensuring the reliability and higher strength of the electrical conductivity of the wiring portion, when forming a copper film layer of 1 μm or more, It is also possible to combine both the dry film forming process and the wet film forming process.

  Moreover, in the flexible double-sided printed wiring board, the thinner the insulating film, the more advantageous from the viewpoints of flexibility and workability of through holes. This is because the thinner the insulating film is, the smaller the misalignment of the wiring patterns on both sides can be. Also, when drilling through holes, the insulating film such as polyimide is etched with a chemical solution. It is necessary. In this regard, according to the method for manufacturing a flexible double-sided printed wiring board according to the present invention, an insulating film having a thickness of 20 μm or less can be used, compared with an insulating film having a thickness of about 40 μm that has been conventionally required. It can be said that it is extremely advantageous in bending resistance.

  Although through holes can be drilled with a laser or the like, burrs are generated in the processed part due to laser processing, and it is necessary to add a process for removing these burrs. The problem of rising.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the examples and comparative examples, (a) determination of wrinkles and (b) measurement of peel strength (peeling strength) were performed by the following methods.

(A) Judgment of wrinkles It was performed by visually observing the surface of the double-sided metal laminated film in a state of being taken out from the sputtering apparatus. The results of this observation are shown in Table 2 as “Good (◯)” in which no wrinkles were found and in which slight wrinkles that did not affect the performance of the double-sided metal laminated film were found slightly. "A wrinkle having a degree of influence on the performance of the double-sided metal laminated film was found as" bad (x) ".

(B) Measurement of etching residue A wiring pattern was formed on the obtained double-sided metal laminated film by a subtractive method. Specifically, the lead width of the sample is 1 mm, and a photosensitive resist (manufactured by Tokyo Ohka Kogyo Co., Ltd., PMERP-RH30PM) is applied to the surface of the copper coating layer of the double-sided metal laminated film to form a pattern with a width of 1 mm. So exposed. Thereafter, the film was developed with an aqueous sodium carbonate solution having a concentration of 0.3% by mass, immersed in a ferric chloride solution (specific gravity 40 ° Baume, temperature 43 ° C.) for 2 minutes, washed with water, and dried. Thereafter, the resist was peeled off using a 4% by mass aqueous sodium hydroxide solution. The obtained wiring pattern was visually observed, and it was confirmed whether there was any undissolved residue (with etching residue) of the Ni-20 mass% Cr layer, which was the underlying metal layer between the leads. The results are shown in Table 2 as “good (◯)” when there is no etching residue, and as “bad (×)” when the etching residual is found in one place.

(C) Measurement of peel strength The initial peel strength was measured by a measurement method based on IPC-TM-650 and NUMBER 2.4.9 after forming a wiring pattern in the same manner as in (b). The measurement conditions at this time were such that the peel angle was 90 °.

  Also, the heat-resistant peel strength is the same as the initial peel strength. After holding the sample at 150 ° C. for 168 hours, taking it out and cooling it to room temperature, the peel angle is 90 ° as with the initial peel strength. The strength was measured.

  In Table 2, if both the initial peel strength on both surfaces (1a, 1b) of the obtained double-sided metal laminate film and the peel strength after the heat test (heat-resistant peel strength) are 400 N / m or more, “good (○ ) ”, And when there was less than 400 N / m, it was expressed as“ bad (×) ”.

Example 1
As the insulating film (1), using a polyimide film having a thickness of 12.5 μm (manufactured by Toray DuPont Co., Ltd., Kapton 50EN), using a continuous sputtering apparatus (4) as shown in FIG. A metal laminated film was produced. In Example 1, the first surface treatment ion gun (9a) was not used, and the dehydration treatment and the first surface treatment were performed on one surface (1a) of the insulating film by the dehydration treatment ion gun (8). Thereafter, the second surface treatment is performed by the second surface treatment ion gun (9b), and then the base metal layers (2a, 2b) and the copper thin film layers (3a, 3b) are applied to the surfaces (1a, 1b) on both sides. A film was formed.

Specifically, the polyimide film (1) is placed in a continuous sputtering apparatus (4), the apparatus (4) is evacuated to 0.1 Pa, and then dehydrated ion gun (8) (anode layer source type). Thus, one surface (1a) of the polyimide film (1) was irradiated with an ion beam to perform dehydration treatment and first surface treatment. At this time, the gas type used was oxygen gas (O ₂ ), and its flow rate was 60 cm ³ / min in terms of 1 atm and 25 ° C. The discharge power of the ion gas was adjusted to 200 W (discharge voltage: 1500 V, discharge current: 133 mA). The treatment time with the ion beam at this time was adjusted to 10 seconds by adjusting the transport speed. After irradiation with an ion beam, the exhaust device (25) was evacuated to 1 × 10 ⁻⁴ Pa. At this time, a turbo molecular pump (manufactured by Mitsubishi Heavy Industries, Ltd.) and a cryocoil (manufactured by Mac Co., Ltd.) were used as the exhaust device (dehydration process, first surface treatment process).

Then, the other surface (1b) of the polyimide film (1) was surface-treated by irradiating an ion beam with the second surface treatment ion gun (9b) (second surface treatment step). At this time, the gas type used was oxygen gas (O ₂ ), and its flow rate was 60 cm ³ / min in terms of 1 atm and 25 ° C. In addition, the discharge power of the ion gas was adjusted to 200 W (discharge voltage: 1500 V, discharge current: 133 mA), and the treatment speed by the ion beam was adjusted to 10 seconds by adjusting the transport speed. In this example, the temperature rise of the insulating film immediately after the dehydration process was 70 ° C. However, as a result of using a tension sensor roll (20) having a function as a cooling roll, before the dehydration process. The temperature rise of the insulating film after completion of the surface treatment process with respect to the temperature of the insulating film could be suppressed to about 30 ° C.

  After the second surface treatment step, the polyimide film (1) is transported before the sputtering apparatus (70), and the sputtering cathode (51) is mounted with a Ni-20 mass% Cr alloy as a target and the sputtering cathode (51). The Cu target was attached to the substrate, and the base metal layer (2b) and the copper thin film layer (3b) were formed by sputtering (first dry film forming step). Thereafter, the polyimide film (1) is conveyed to the sputtering device (71), and a Ni-20 mass% Cr alloy is mounted on the sputtering cathode (60) as a target, and a Cu target is mounted on the sputtering cathode (61). The base metal layer (2a) and the copper thin film layer (3a) were formed by sputtering (second dry film forming step). At this time, the thickness of the base metal layer (2a, 2b) was 10 nm, and the thickness of the copper thin film layer (3a, 3b) was 0.1 μm. The time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound up by the winding roll (7) was 10 minutes.

  After the second dry film forming step, the obtained double-sided metal laminated film is taken out from the continuous sputtering apparatus (4), and the surface is visually observed. It was not confirmed.

  Flexible double-sided printed wiring by forming a copper plating layer with a film thickness of 8μm on this double-sided metal laminated film by electroplating using sulfuric acid copper sulfate aqueous solution and forming a wiring pattern by subtractive method A substrate was obtained. By visually observing the surface of this flexible double-sided printed wiring board, (b) etching residue measurement was performed, and as a result, no etching residue was found.

  Furthermore, as a result of measuring the (c) peel strength of the obtained flexible double-sided printed wiring board, both the initial peel strength and the heat-resistant peel strength on both sides were 400 N / m or more. These results are shown in Table 2.

(Examples 2 to 7)
A double-sided metal laminate film was obtained by performing dehydration treatment and surface treatment in the same manner as in Example 1 except that the type of ion gas used and the gas flow rate were adjusted as described in Table 1. In Examples 2 to 7, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes. .

  For these double-sided metal laminated films, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

(Example 8)
By adjusting the irradiation conditions of the dehydration ion gun (8), the dehydration ion gun (8) only performs dehydration treatment, and the first surface treatment ion gun (9a) performs the first surface treatment, In the same manner as in Example 1, a double-sided metal laminated film was obtained. In Example 8, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

Example 9
By adjusting the output (cooling power) of the tension sensor roll (20) as a cooling roll, the temperature rise of the insulating film before the dehydration process and after the second surface treatment process is adjusted to about 60 ° C. Except having done, it carried out similarly to Example 1, and obtained the double-sided metal laminated film. In Example 9, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

(Example 10)
In the dehydration treatment step and the surface treatment step, a double-sided metal laminated film was obtained in the same manner as in Example 1 except that the flow rate of the ion gas was 40 cm ³ / min in terms of 1 atm and 25 ° C. In Example 10, the discharge state became slightly unstable upon irradiation with ion beams, and micro arcs were observed during the treatment. In Example 10, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound up by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

(Example 11)
In the dehydration treatment step and the surface treatment step, a double-sided metal laminated film was obtained in the same manner as in Example 1 except that the flow rate of the ion gas was 80 cm ³ / min in terms of 1 atm and 25 ° C. In Example 11, the discharge state became slightly unstable upon irradiation with ion beams, and micro arcs were generated during the treatment. In Example 11, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

(Comparative Example 1)
Instead of dehydration treatment using the dehydration ion gun (8), the examples were the same except that after vacuum evacuation to 0.1 Pa, the insulating film was left in the vacuum chamber (5) for 10 seconds for vacuum drying. In the same manner as in Example 8, a double-sided metal laminated film was obtained. In Comparative Example 1, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

(Comparative Example 2)
Insulation film was heated to 50 ° C. using an infrared heater instead of dehydration treatment with an ion gun (8), and was heated and dried at this temperature for 10 seconds, and a tension sensor roll (20) A double-sided metal laminate film was obtained in the same manner as in Example 8 except that the output (cooling power) as a cooling roll was adjusted to be low. In Comparative Example 2, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

(Comparative Example 3)
In place of the dehydration treatment by the deionization ion gun (8), an infrared heater was used to heat the insulating film to 100 ° C., and heat drying at this temperature for 10 seconds was performed in the same manner as in Comparative Example 2. Thus, a double-sided metal laminated film was obtained. In Comparative Example 3, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) the etching residue measurement was performed. In Comparative Example 3, in (a) the measurement of wrinkles, wrinkles were found on the surface of the double-sided metal film, and (c) the peel strength was not measured. These results are shown in Table 2.

(Comparative Example 4)
Dehydration treatment Instead of dehydration treatment with an ion gun (8), using an infrared heater, the insulating film was heated to 50 ° C., and the conveyance speed was adjusted, so that heating and drying were performed at this temperature for 50 seconds. Obtained a double-sided metal laminate film in the same manner as in Comparative Example 2. In Comparative Example 4, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 50 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) measurement of etching residue and (c) measurement of peel strength were performed. These results are shown in Table 2.

(Comparative Example 5)
A double-sided metal laminate film was obtained in the same manner as in Example 1 except that the discharge power of the ion gas was adjusted to 400 W (discharge voltage: 2500 V, discharge current: 160 mA). In Comparative Example 5, the temperature rise of the insulating film immediately after the dehydration process was 100 ° C. However, as a result of using a tension sensor roll (20) having a function as a cooling roll, before the dehydration process. The temperature rise of the insulating film after completion of the surface treatment process relative to the temperature of the insulating film was suppressed to about 30 ° C. In Comparative Example 5, the time from when the insulating film (1) was unwound from the unwinding roll (6) to when it was wound by the winding roll (7) was 10 minutes.

  For this double-sided metal laminate film, (a) wrinkles were measured in the same manner as in Example 1. Moreover, the wiring pattern was formed with respect to this double-sided metal laminated film similarly to Example 1, and (b) the etching residue measurement was performed. In Comparative Example 5, in (a) the measurement of wrinkles, wrinkles were found on the surface of the double-sided metal film, and (c) the peel strength was not measured. These results are shown in Table 2.

(Evaluation)
In Examples 1 to 9 belonging to the technical scope of the present invention, there was no wrinkle and no etching residue. Moreover, it was confirmed that the initial peel strength and the heat-resistant peel strength are also excellent.

In addition, it was confirmed that the double-sided metal laminated films obtained in Examples 10 and 11 had practically no problem characteristics, but the discharge state became slightly unstable during processing, and the microarc Occurrence was seen. From these results, it is predicted that when the flow rate of the ion gas is less than 40 cm ³ / min or more than 80 cm ³ / min, the discharge state becomes more unstable and gradually uniform ion beam processing becomes difficult. .

  In Comparative Example 1, since the dehydration process was performed by vacuum drying, the dehydration of the insulating film did not proceed sufficiently, and etching residues were observed between the leads after the formation of the wiring pattern by the subtractive method.

  Comparative Examples 2 and 3 are examples in which the dehydration process was performed by heating with an infrared heater. In Comparative Example 2, since the heating temperature was as low as 50 ° C., dehydration did not proceed, and etching residues were observed after the formation of the wiring pattern as in Comparative Example 1. In Comparative Example 3, since the heating temperature was as high as 100 ° C., generation of wrinkles was confirmed after the formation of the base metal layer by the sputtering method.

  Comparative Example 4 is an example in which the dehydration process was performed using an infrared heater over a sufficiently long time. For this reason, in Comparative Example 4, the time from when the insulating film was unwound from the unwinding roll until it was wound up by the take-up roll was about five times that of Examples 1-12.

  Comparative Example 5 is an example in which the dehydration process is performed by a conventional ion beam irradiation method. Immediately after the dehydration process, the temperature rise of the insulating film reaches about 100 ° C. For this reason, even if it was a case where it cooled enough with a cooling roll after that, generation | occurrence | production of the wrinkle after base metal layer formation was not fully suppressed.

DESCRIPTION OF SYMBOLS 1 Insulating film 1a, 1b Surface 2a, 2b Underlying metal layer 3a, 3b Copper thin film layer 4 Continuous sputtering apparatus 5 Vacuum chamber 6 Unwinding roll 7 Winding roll 8 Dehydration ion gun 9a First surface treatment ion gun 9b Second surface treatment ion gun 10-18 Guide roll 20-22 Tension sensor roll 25 Exhaust device 30, 31 Feed roll 40, 41 Cooling can roll 50, 51 Sputtering cathode 60, 61 Sputtering cathode 70 First dry film forming device 71 Second dry film forming device

Claims (7)

A method for producing a double-sided metal laminate film in which a copper coating layer is formed on the surface of the base metal layer after forming the base metal layer by dry plating without using an adhesive on both sides of the insulating film,
Dehydration by irradiating at least one surface of the insulating film with an ion beam in a vacuum atmosphere, dehydrating while suppressing the temperature rise to 90 ° C. or less, and exhausting water vapor generated by the dehydration Processing steps;
A first surface treatment step of performing surface treatment by irradiating one surface of the insulating film with an ion beam;
A second surface treatment step of irradiating the other surface of the insulating film with an ion beam for surface treatment;
A first dry composition in which the base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on any surface of the surface-treated insulating film by a dry plating method. A membrane process;
First, the base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on the surface of the insulating film on which the copper thin film layer is not formed by dry plating. 2 dry film forming step,
A method for producing a double-sided metal laminate film.   The manufacturing method of the double-sided metal laminated film of Claim 1 which performs the said dehydration process process and a 1st surface treatment process simultaneously.   The double-sided metal laminate film according to claim 1 or 2, wherein the ion beam irradiation uses an ion gas composed of at least two kinds of mixed gases selected from argon, nitrogen, oxygen, or a group thereof. Production method. The manufacturing method of the double-sided metal laminated film in any one of Claims 1-3 whose vacuum degree in a 1st surface treatment process and a 2nd surface treatment process is 1 * 10 < ^-4 > Pa-1Pa. Dehydration processing step, the flow rate of the ion gas in the first surface treatment step and the second surface treatment step, 1 atm, at 25 ° C. terms, and 40cm ³ / min~80cm ³ / min, claim 1 The manufacturing method of the double-sided metal laminated film of description. An apparatus for producing a double-sided metal laminate film,
A vacuum chamber, and a roll-to-roll film processing apparatus disposed in the vacuum chamber,
The roll-to-roll film processing apparatus includes an unwinding roll, a winding roll, and a film track between these rolls,
A dehydrating ion gun for irradiating at least one surface of the insulating film with an ion beam and dehydrating the insulating film;
An exhaust device for exhausting water vapor generated by the dehydration treatment;
A first surface treatment ion gun that performs surface treatment by irradiating one surface of the insulating film with an ion beam;
On the downstream side of the first surface treatment ion gun, disposed on the opposite side of the first surface treatment ion gun across the track of the insulation film, and irradiating the other surface of the insulation film with an ion beam to perform surface treatment. A second surface treatment ion gun;
A base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on any surface of the insulating film disposed on the downstream side of the second surface treatment ion gun and subjected to the surface treatment. A first dry film forming apparatus for forming a film;
On the downstream side of the first dry film forming apparatus, on the opposite side of the first dry film forming apparatus across the track of the insulating film, on the surface of the insulating film on which the copper thin film layer is not formed A second dry film forming apparatus for sequentially forming a copper thin film layer constituting part or all of the base metal layer and the copper coating layer;
Comprising
Manufacturing equipment for double-sided metal laminate film. An apparatus for producing a double-sided metal laminate film,
A vacuum chamber, and a roll-to-roll film processing apparatus disposed in the vacuum chamber,
The roll-to-roll film processing apparatus includes an unwinding roll, a winding roll, and a film track between these rolls,
A first surface treatment ion gun for performing dehydration treatment and surface treatment by irradiating one surface of the insulating film with an ion beam;
An exhaust device for exhausting water vapor generated by the dehydration process downstream of the first surface treatment ion gun;
A second surface treatment ion gun disposed on the opposite side of the first surface treatment ion gun across the track of the insulation film on the downstream side of the exhaust device and irradiating the other surface of the insulation film with an ion beam;
A base metal layer and a copper thin film layer constituting a part or all of the copper coating layer are sequentially formed on any surface of the insulating film disposed on the downstream side of the second surface treatment ion gun and subjected to the surface treatment. A first dry film forming apparatus for forming a film;
On the downstream side of the first dry film forming apparatus, on the opposite side of the first dry film forming apparatus across the track of the insulating film, on the surface of the insulating film on which the copper thin film layer is not formed A second dry film forming apparatus for sequentially forming a copper thin film layer constituting part or all of the base metal layer and the copper coating layer;
Comprising
Manufacturing equipment for double-sided metal laminate film.