JP5995145B2 - Resin film surface treatment method, resin film deposition method, and metallized resin film substrate production method - Google Patents

Description

  In the present invention, in a reduced-pressure atmosphere, the resin film wound in a roll shape is unwound from an unwinding shaft and conveyed by roll-to-roll, and at least one surface of the resin film is surface-treated, and the resin film is The present invention relates to a surface treatment method for a resin film wound around a winding shaft, a film formation method for a resin film, and a method for manufacturing a metallized resin film substrate.

  In a liquid crystal panel, a notebook computer, a digital camera, a mobile phone, and the like, a flexible wiring board in which a wiring pattern is formed on a resin film is used. This flexible wiring board is manufactured by patterning a metallized resin film substrate with a metal film formed on one or both sides of the resin film. In recent years, however, the wiring pattern has become increasingly more delicate and dense. Accordingly, there is a demand for smooth metalized resin film substrates free from scratches and wrinkles.

  The manufacturing method of such a metallized resin film substrate is conventionally a method of manufacturing by attaching a metal foil to a resin film with an adhesive (manufacturing method of a three-layer substrate), coating a metal foil with a resin solution, and then drying (A casting method), and a method of forming a metal film on a resin film by a vacuum film formation method alone or by using a combination of a vacuum film formation method and a wet plating method (Metal) As a vacuum film forming method used for the metalizing method, there are a vacuum deposition method, a sputtering method, an ion plating method, an ion beam sputtering method and the like performed in a reduced pressure atmosphere.

Regarding this metallizing method, Patent Literature 1 describes a method of forming a conductor layer by sputtering copper after sputtering a chromium layer on a polyimide insulating layer.
Patent Document 2 discloses a flexible circuit board in which a first metal thin film by sputtering using a copper nickel alloy as a target and a second metal thin film by sputtering using copper as a target are formed on a polyimide film. A material is disclosed.
The film formation by these sputtering methods is generally excellent in adhesion, but it is said that the thermal load applied to the resin film as the substrate is larger than other vacuum vapor deposition methods. It is also known that when a large thermal load is applied to the resin film during film formation, the film is likely to be wrinkled.

Therefore, a sputtering web coater equipped with a can roll is generally used in the step of forming a metallized resin film substrate by forming a film on the resin film such as the polyimide film by a vacuum film forming method.
This device performs sputtering while winding a roll-to-roll resin film around a can roll in which a refrigerant is circulated, and immediately cools heat generated in the resin film by film formation on the front side from the back side. Therefore, the adverse effect of the heat load during film formation can be suppressed, and thus generation of wrinkles is effectively prevented.

For example, Patent Document 3 discloses an unwinding type (roll-to-roll type) vacuum sputtering apparatus which is an example of a sputtering web coater.
This unwinding / winding-type vacuum sputtering apparatus is provided with a cooling roll serving as a can roll. Further, a sub-roll is provided at least on the film feeding side or the feeding side of the cooling roll, thereby controlling the resin film to be in close contact with the cooling roll.

By the way, in the vacuum film forming method using the sputtering web coater, when the charged resin film is conveyed by roll-to-roll in the film forming apparatus under a reduced pressure atmosphere, the resin film and the metal parts of the film forming apparatus are used. In some cases, unintended discharge (hereinafter referred to as abnormal discharge) may occur.
This abnormal discharge damages the surface of the resin film and the film after film formation, impairs the quality of the product, and in some cases may prevent continuous film formation. In addition, when abnormal discharge occurs, not only when continuous film formation cannot be maintained, but also when the surface of the resin film or the film after film formation is damaged, it is not suitable as a product. And productivity is greatly impaired.

Such charging of the resin film during film formation occurs in the film forming apparatus while being transported by roll-to-roll, and when the resin film before film formation attached to the unwinding shaft is already charged. There are two known states.
In contrast to the former, for example, Patent Document 4 discloses disposing a static eliminating device between a film forming unit and a winding unit in the film forming device in order to prevent charging by sputtering. This technique is effective for charging during film formation, but the resin film wound in the form of a roll before film formation (hereinafter simply referred to as a resin film roll) is already charged as in the latter case. In some cases, the effect is reduced, and discharge in the film forming apparatus cannot be avoided.

  In general, the resin film roll may be charged during the manufacturing process, and the charging tends to become more prominent as the length becomes longer.

Japanese Patent Laid-Open No. 2-98994 JP-A-6-97616 Japanese Patent Laid-Open No. 62-247073 JP 2004-256885 A

  Therefore, the object of the present invention is to prevent abnormal discharge when transporting a resin film under a reduced pressure atmosphere, and even a long resin film does not harm the resin film or the formed film. The surface treatment method of this, the film-forming method of a resin film, and the manufacturing method of a metallized resin film board | substrate are provided.

The first invention of the present invention that solves the above problems is based on roll-to-roll by unwinding a resin film from an unwinding roll in which a resin film having a thickness of 10 to 50 μm is wound in a roll shape in a reduced-pressure atmosphere. The charge potential of the resin film is measured during conveyance, and at least one surface of the resin film having the charge potential in the range of −7 kV to +7 kV is subjected to surface treatment and wound on a take-up roll. This is a surface treatment method for a resin film.

  According to a second aspect of the present invention, there is provided a surface treatment method for a resin film, wherein the resin film wound in a roll shape according to the first aspect has a length of at least 500 m.

  According to a third aspect of the present invention, there is provided a resin film surface treatment method, wherein the surface treatment in the first and second aspects is a metal film formation treatment using a sputtering method.

4th invention of this invention is a manufacturing method of the metallized resin film board | substrate provided with a metal film on the surface of a resin film without using an adhesive agent , Comprising: The thickness of the resin film is 10-50 micrometers, pressure reduction Under the atmosphere, the resin film is unwound from the unwinding roll in which the resin film is wound in a roll shape, and the charge potential of the resin film is measured while being conveyed by roll-to-roll. A method for producing a metallized resin film substrate, comprising: forming a metal film using a sputtering method on at least one surface of a resin film in a range of 7 kV to +7 kV and winding the film on a take-up roll. .

  According to a fifth aspect of the present invention, there is provided a metallized resin film substrate in which the metal film according to the fourth aspect is laminated in order from the resin film surface to a base metal film containing Ni or a Ni alloy and a Cu film. It is a manufacturing method.

6th invention of this invention is a manufacturing method of the metallized resin film board | substrate provided with a metal film on the surface of a resin film without interposing an adhesive agent , Comprising: The thickness of the resin film is 10-50 micrometers, pressure reduction Under the atmosphere, the resin film is unwound from the unwinding roll in which the resin film is wound in a roll shape, and the charge potential of the resin film is measured while being conveyed by roll-to-roll. At least one surface of the resin film in the range of 7 kV to +7 kV is subjected to a metal film forming process using a sputtering method, wound on a winding roll, and then a Cu film on the metal film using a wet plating method. Is a method for producing a metallized resin film substrate.

According to the present invention, since discharge from the resin film does not occur in the surface treatment apparatus under a reduced pressure atmosphere, the quality of the product is improved without damaging the resin film or the film formed by the surface treatment.
Moreover, since the length of the resin film can be increased without stopping the apparatus due to electric discharge, it contributes to the improvement of productivity.

It is a schematic diagram which shows one specific example of the apparatus which forms into a film on the surface of the resin film by a roll-to-roll system. It is a figure which shows the electric potential measurement result of Example 1. FIG. FIG. 6 is a diagram showing a potential measurement result of Comparative Example 1.

As an example of an embodiment of the resin film surface treatment method of the present invention, as shown in FIG. 1, vacuum film formation is performed by sputtering on a resin film that is continuously conveyed in a roll-to-roll system in a vacuum container. The apparatus will be specifically described.
In FIG. 1, a film forming apparatus (sputtering web coater) 1 includes a can roll 3 in which a resin film F unwound from an unwinding roll 2 of a resin film roll on which a resin film is wound in a vacuum chamber 10. The film is wound on a winding roll 4 after being subjected to a predetermined film forming process while being wound around and cooled.

The vacuum chamber 10 is equipped with various devices such as a dry pump, a turbo molecular pump, and a cryocoil (not shown). After these pressures are reduced to an ultimate pressure of about 10 ⁻⁴ Pa, a sputtering gas is introduced. The pressure is adjusted to about 0.1 to 10 Pa.
A known gas such as argon is used as the sputtering gas.
The shape and material of the vacuum chamber 10 are not particularly limited as long as they can withstand a reduced pressure state, and various types can be used.

In the conveyance path from the unwinding roll 2 to the can roll 3, a free roll 11 that guides the resin film F so that the resin film F is conveyed in close contact with the outer peripheral surface of the can roll 3, and a tension that measures the tension. The resin film is conveyed by appropriately arranging a motor-driven feed roll 13 and the like for adjusting the circumferential speed of the sensor roll 12 and the can roll 3.
Similarly to the above, a motor-driven feed roll 13, a tension sensor roll 12, and a free roll 11 are also arranged on the transport path from the can roll 3 to the take-up roll 4 as appropriate.

  Plate magnetron sputtering cathodes 6, 7, 8, and 9 are provided at positions facing the outer peripheral surface of the can roll 3 along the transport path of the resin film F, whereby a metal film is formed on the surface of the resin film F. A metallized resin film S (in some cases, a metallized resin film substrate) is formed.

  When a plate-like target is used, nodules (growth of foreign matter) may occur on the target. If this is a problem, no nodules are generated and the target is used efficiently. A rotary target may be used. Further, in the case where the heat-loading process performed by the film forming apparatus 1 is a vacuum film forming process such as CVD (chemical vapor deposition) or vacuum vapor deposition other than the sputtering process, the magnetron sputtering cathodes 6, 7, 8, 9 are used. Instead of this, another vacuum film forming means is provided.

Examples of the resin film used in the roll-to-roll surface treatment apparatus include a resin film such as a polyethylene terephthalate (PET) film and a heat resistant resin film such as a polyimide film.
In particular, as the resin film used for the metallized resin film substrate, polyimide film, polyamide film, polyester film, polytetrafluoroethylene film, polyphenylene sulfide film, polyethylene naphthalate film, liquid crystal polymer film, etc. Can be mentioned.

  These resin films are suitable as a metallized resin film substrate used for manufacturing a flexible wiring board from the viewpoints of flexibility, practically necessary strength, and electrical insulation suitable as a wiring material. The thickness is appropriately selected according to the use, but a thickness of 10 to 50 μm is mainly used.

  A high-quality metallized resin film can be obtained by sputtering a metal film on the resin film using the film forming apparatus 1 (sputtering web coater). For example, it is possible to produce a high-quality metallized resin film in which a film made of Ni or Ni alloy called a base metal film on the surface of the resin film and a Cu film are further laminated on the surface of the base metal film.

Here, as the base metal film, various known Ni alloys such as Ni metal or Ni—Cr alloy, Inconel, Cond Tantan, and Monel can be used, but the composition thereof is the electric insulation and migration resistance of the metallized resin film substrate. It is selected according to desired characteristics such as sex.
The Cu film is called a seed layer, and a Cu metal film may be further laminated using a wet plating method in order to further increase the thickness of the metal film obtained by sputtering film formation.

The film thicknesses of the base metal film and the Cu film are preferably 3 to 50 nm for the base metal film and 0.01 to 1 μm for the Cu film, respectively. In addition, when using a wet plating method, a combination of a wet plating method such as a case where a metal film is formed only by an electroplating process, and an electroless plating process as a primary plating and an electrolytic plating process as a secondary plating, etc. There is a case to do.
The film thickness of the Cu metal film laminated using the wet plating method is appropriately selected according to the patterning method of the flexible wiring board described later, but it is 0.5 with the Cu film obtained by sputtering film formation. ˜12 μm is preferred. Various conditions of a general wet plating method can be employed for the wet plating process.

By patterning the thus obtained metallized resin film substrate using a subtractive method or a semi-additive method, a flexible wiring board used for a liquid crystal television, a mobile phone or the like is obtained.
Here, the subtractive method is a method of manufacturing a flexible wiring board by performing patterning by removing a metal film (a film made of the Ni alloy or the like and a Cu film) not covered with a resist by etching. On the other hand, the semi-additive method is a process of patterning by depositing a Cu film on a Cu film not covered with a resist by wet plating, removing the resist, and then removing the metal layer other than the Cu film by etching. And it is the method of manufacturing a flexible wiring board.

  As described above, the film forming apparatus (sputtering web coater) is taken as an example, and the case where a metal film such as Ni alloy or Cu is laminated on the resin film has been described. The film forming apparatus according to the present invention is a metallized resin. It is not limited to the use for producing the film, and can be suitably used for forming an oxide film, a nitride film, a carbide film, etc. in addition to the metal film.

  In addition to the film forming process described above, the film forming apparatus (sputtering web coater) of the present invention can also add a plasma process or an ion beam process as a pre-process for film formation. These plasma treatments and ion beam treatments modify the surface for the purpose of improving the adhesion between the film to be deposited and the resin, or reduce the moisture contained in the resin, especially in the metal film deposition. This is done for the purpose of preventing corrosion.

  Of course, the surface treatment method of the present invention is not limited to the vacuum film formation process. For example, an apparatus for independently performing the plasma treatment or ion beam treatment that can be added to the film formation process, for a resin film, Needless to say, the present invention can also be applied to various surface treatments carried by a roll-to-roll method in a reduced-pressure atmosphere.

Next, charging of the resin film will be described.
Generally, a resin film called plastic is an insulator and has a property of being easily charged as compared with a conductor such as metal.
As a mechanism for generating static electricity, contact, friction, and separation between different substances are well known, but electric charges are generated by friction even between the same substances. When the generated charge stays on the substance, it becomes charged and static electricity is generated.
For example, when a positive charge is present on one surface of a certain resin film, the resin film is a dielectric, so the other surface is in a polarized state due to the presence of a negative charge. When this resin film is brought into contact with another resin film surface, another resin film generates an opposite charge (in this case, a negative charge) on the contact surface side, and is polarized to a positive charge on the surface opposite to the contact surface. Thus, it is considered that the charge between the films is stabilized.

In the production of a resin film roll, or in a production process using this resin film roll, the resin film moves while in contact with the roller in the roll-to-roll conveyance, and the resin film and the roller, and the resin film come into contact with each other and are peeled off. In a scene where friction occurs, the resin film is charged and static electricity is generated.
In other words, the roll-to-roll transport constantly generates phenomena such as friction and peeling that are easily charged for the resin film, and as described above, since there is a charge that does not easily move on the resin film, When charging is performed by contact with a roller or peeling, a resin film roll having a high charging potential is obtained unless measures such as static elimination such as an ion blower are taken before winding the roll.

Further, the high charging potential of the resin film roll is considered to be due to the shape similar to the multilayer capacitor.
In general, in order to increase the capacitance of the multilayer capacitor, the electrode area is increased by laminating several dielectric layers. Similarly, since the resin film is an insulator, the more the resin film is stacked, the larger the area where the films come into contact with each other. The larger the contact area, the more the film is wound on the roll and the roll is unwound. Charge amount accumulates. Further, the longer the resin film, the more the rolls need to be wound. This also increases the contact area and increases the charging potential.

When the resin film is unwound from the resin film roll, the electric charge accumulated in the roll is not uniformly charged over the entire length of the resin film, and the absolute value of the charging potential of the resin film at the start of unwinding is extremely small. As the process proceeds, the absolute value of the charging potential gradually increases, and the absolute value of the charging potential of the resin film immediately before the end of unwinding tends to be maximized.
Although the act of unwinding itself is a factor that newly accumulates the charge amount, it is one factor that shows such a tendency, but the main factor is that the electric charge moves to the remaining roll side when unwinding, and the electrical stability It is thought that it may be for maintaining.

In a surface treatment that is transported by roll-to-roll in a reduced-pressure atmosphere, abnormal discharge that occurs between the resin film and the metal parts of the film forming device occurs when the remaining unloaded resin film on the device is low However, the longer the resin film roll is, the more easily abnormal discharge occurs for the reason described above.
As a means for preventing this abnormal discharge, it is conceivable to go through the static elimination part before the surface treatment, but it is impossible to install an existing static elimination device such as an ion blower because it is under a reduced pressure atmosphere, There are various restrictions such as the ability to be limited.

Therefore, in order to prevent abnormal discharge, it is effective to limit the charging potential of the resin film to be surface-treated.
The inventor has found by testing that the abnormal discharge can be reliably prevented if the charging potential of the resin film is in the range of −7 kV to +7 kV (within 7 kV in absolute value) over the entire length. This charging potential is not the value of the surface of the resin film roll wound in the form of a roll, but the value of the surface of the resin film unwound from the resin film roll. As described above, the charging potential of the resin film immediately before the end of unwinding Is particularly important in preventing abnormal discharge.

When measuring the charging potential of the resin film, it is necessary to take into account the effect of charging that occurs when unwinding. For example, a resin film roll in which a resin film is wound around an unwinding roll like the sensor 5 in FIG. After unwinding, it is desirable to measure at a passing point on the conveyance path to the can roll 3.
Moreover, in order to manufacture a resin film roll having a low absolute value of the charging potential, a specific manufacturing method is not used, and a known means for preventing charging and a means for removing static electricity may be combined.

  It goes without saying that abnormal discharge may occur if the charging potential is outside the above range regardless of the length of the resin film, but considering the productivity, the length of the resin film is preferably at least 500 m or more. . Of course, the longer the length, the higher the productivity. However, the longer the length, the greater the diameter and weight of the resin film roll, which requires special handling. Considering the decrease in stability and the like, there is a limit naturally, and the upper limit is about 5000 m.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.

As the long resin film F, a commercially available polyimide film (Upilex (registered trademark) 35SGA manufactured by Ube Industries, Ltd.) having been subjected to static elimination treatment was prepared having a length of 2000 m, a width of 500 mm, and a thickness of 35 μm.
As the resin film processing apparatus, a roll-to-roll film forming apparatus 1 as shown in FIG. 1 was used.

  The prepared polyimide film is arranged on the unwinding roll 2, and an alloy target made of nickel-chromium (manufactured by Sumitomo Metal Mining Co., Ltd.) is arranged for the base metal film on the magnetron sputtering cathode 6, and the magnetron sputtering cathodes 7, 8, In 9, a copper target (manufactured by Sumitomo Metal Mining Co., Ltd.) was arranged for the Cu film.

First, the gas was evacuated to 5 Pa using a dry pump (not shown), then evacuated to 1 × 10 ⁻⁴ Pa using a turbo molecular pump and a cryocoil, and 200 sccm of argon gas was introduced in the vicinity of each sputtering cathode. The polyimide film was 2 m / min. The film was formed by sputtering while being conveyed, and a base metal film having a thickness of 15 nm and a Cu film having a thickness of 100 nm were obtained, and the film formation of the entire 2000 m polyimide film prepared without occurrence of abnormal discharge was completed.

While forming the film, the charging potential was measured by the sensor 5 installed between the free roll 11 and the tension sensor roll 12 arranged in the path between the unwinding roll 2 and the can roll 3.
The potential immediately before the film formation process was −6.8 kV.
FIG. 2 shows the potential measurement result with respect to the treatment length.

The film was formed under the same conditions as in Example 1 except that a commercially available polyimide film (upilex (registered trademark) 35SGA manufactured by Ube Industries, Ltd.) subjected to static elimination treatment with a length of 1500 m was prepared. The film formation was finished.
The potential immediately before completion of the film forming process measured by the sensor 5 was −3.4 kV.

(Comparative Example 1)
Film formation was performed under the same conditions as in Example 1 except that a commercially available polyimide film having a length of 2000 m that had not been subjected to static elimination treatment (“UPILEX (registered trademark) 35SGA” manufactured by Ube Industries, Ltd.) was prepared.
In Comparative Example 1, abnormal discharge occurred at a time exceeding 1750 m from the start of processing, and the operation of the apparatus was stopped.

When the surface of the polyimide film being conveyed in the film forming apparatus 1 was inspected, scratches due to discharge marks were found.
The potential immediately before the occurrence of abnormal discharge measured by the sensor 5 was −8.8 kV.
FIG. 3 shows the result of potential measurement with respect to the processing length until abnormal discharge occurs.

(Comparative Example 2)
Film formation was performed under the same conditions as in Example 1, except that a commercially available polyimide film having a length of 1500 m that was not subjected to static elimination treatment (“UPILEX (registered trademark) 35SGA” manufactured by Ube Industries, Ltd.) was prepared.
In Comparative Example 2, abnormal discharge occurred at a time exceeding 1150 m from the start of processing, and the operation of the apparatus was stopped.

When the surface of the polyimide film being conveyed in the film forming apparatus 1 was inspected, scratches due to discharge marks were found.
The potential immediately before the occurrence of abnormal discharge measured by the sensor 5 was −7.8 kV.

From the above, referring also to FIG. 2 and FIG. 3, in Example 1 and Example 2 in which abnormal discharge did not occur, the charging potential measured by the sensor 5 was within the range of −7 kV to +7 kV over the entire length of the polyimide film. On the other hand, in Comparative Example 1 and Comparative Example 2 in which abnormal discharge occurred, it can be seen that the potential exceeded the range of −7 kV to +7 kV immediately before the abnormal discharge occurred.
It can also be seen that the abnormal discharge does not depend on the length of the polyimide film.

1 Film deposition system (sputtering web coater)
2 Unwinding roll 3 Can roll 4 Winding roll 5 Sensor 6, 7, 8, 9 Magnetron sputtering cathode 10 Vacuum chamber 11 Free roll 12 Tension sensor roll 13 Motor driven feed roll F Resin film S Metallized resin film

Claims (6)

Under a reduced pressure atmosphere, the resin film is unwound from an unwinding roll in which a resin film having a thickness of 10 to 50 μm is wound in a roll shape, and the charged potential of the resin film is measured while being conveyed by roll-to-roll. A surface treatment method for a resin film, wherein a surface treatment is applied to at least one surface of a resin film having a charged potential in a range of −7 kV to +7 kV, and the film is wound on a winding roll.   The surface treatment method for a resin film according to claim 1, wherein the resin film wound in a roll has a length of at least 500 m.   The resin film surface treatment method according to claim 1, wherein the surface treatment is a metal film formation process using a sputtering method. A method for producing a metallized resin film substrate comprising a metal film on the surface of a resin film without using an adhesive,
The resin film has a thickness of 10 to 50 μm,
Under a reduced pressure atmosphere, the resin film is unwound from an unwinding roll in which the resin film is wound in a roll shape, and the charged potential of the resin film is measured while being conveyed by roll-to-roll. A method for producing a metallized resin film substrate, comprising forming a metal film using a sputtering method on at least one surface of a resin film in a range of 7 kV to +7 kV, and winding the film on a winding roll.   5. The method for producing a metallized resin film substrate according to claim 4, wherein the metal film is laminated in the order of a base metal film containing Ni or Ni alloy and a Cu film from the resin film surface. A method for producing a metallized resin film substrate comprising a metal film on the surface of a resin film without using an adhesive,
The resin film has a thickness of 10 to 50 μm,
Under a reduced pressure atmosphere, the resin film is unwound from an unwinding roll in which the resin film is wound in a roll shape, and the charging potential of the resin film is measured during conveyance by roll-to-roll, and the charging potential is -7 kV. After forming a metal film using a sputtering method on at least one surface of a resin film in a range of ~ + 7 kV and winding it on a winding roll, a Cu film is formed on the metal film using a wet plating method. A method for producing a metallized resin film substrate, comprising laminating layers.

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