JP2005076120A - Vacuum film-forming apparatus and film-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum film-forming apparatus which can easily wind a film substrate, on which a film is to be formed, around a metal roll and can stably form a multilayered film on the surface of the film substrate wound around the metal roll. <P>SOLUTION: The vacuum film-forming apparatus is at least equipped with a part for winding off the long film substrate, a pair of nip rollers for sandwiching the film substrate which has been wound off, the metal roll around which the film substrate is wound, a charged particle-emitting part for charging the film substrate and film-forming parts for forming the film on the surface of the film substrate. Here, the metal roll is located right below the nip rollers, the charged particle-emitting part is located obliquely below the nip rollers, close to the upstream surface in regard to the direction of rotation of the metal roll, and the film-forming parts are located below the metal roll. The charged particle-emitting part is made of a material which emits at least one kind of charged particles which are generated via hollow cathode discharge and accelerated by a voltage higher than -5.0 kV. The vacuum film-forming apparatus is used in a film-forming method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vacuum film forming apparatus for forming a thin film on the surface of a film substrate wound around a metal roll, and a thin film forming method using the same.

In recent years, functional films having various functions by forming a thin film on the surface of a substrate such as plastic have been actively developed. In general, a method for obtaining a thin film having high functionality and high quality under vacuum is well known. The field of application is wide. In the package field, there are thin films that impart gas barrier properties, and in the display field, there are thin films that impart various functions to display members. In recent years, research and development has been actively conducted on multilayering of thin films and an increase in film forming speed. There are two methods for obtaining a multilayer film: a method in which a single film corresponds to one film forming unit, and a method in which a base material is reciprocated in a part of the film forming unit. In the former, the movement of the substrate is minimal, but the film forming units corresponding to the target number of films are necessary. In the latter case, the movement of the base material becomes complicated, but the film formation unit is prepared for each type of film, and by reciprocating the base material to that part, a multilayer film laminated as many times as it passes through the film formation unit is obtained. If the temperature or the discharge power is increased, the thermal load increases and the base material may be deformed. However, the thermal load can be dispersed by passing the base material many times. One way to pass the substrate through the film formation unit many times is to wrap the substrate around a metal roll and rotate it, eliminating the need for a large substrate transport system and using a simple device. A multilayer film can be formed. However, in the case of this method, since the film base material is wound around the metal roll while maintaining the tension, there is a disadvantage that it is necessary to fix the film base material manually using an adhesive tape in the atmosphere. In order to improve the above-mentioned problems, a method of forming a thin film on the film base material by winding it around the cooling roll after being charged in advance so that the film base material does not float from the cooling roll during thin film formation, and Such an apparatus has been proposed (see, for example, Patent Document 1).
JP 2002-358633 A

  An object of the present invention is to provide a vacuum film forming apparatus capable of easily winding a film base material on which a thin film is formed around a metal roll, and capable of forming a multilayer thin film stably on the surface of the film base material wound around the metal roll, and its formation. It is to provide a membrane method.

  The invention according to claim 1 of the present invention is a vacuum film forming apparatus for forming a thin film on a film substrate, in order to sandwich the unwinding part of the long film substrate and the unwound film substrate from both sides. A pair of kneading rolls, a metal roll for winding a film base directly under the nip roll, and a film base at a position close to the upstream surface in the rotation direction of the metal roll under the nip roll. And a plurality of film forming chambers for forming a thin film on the surface of the film substrate under the metal roll, and the film substrate between the nip roll and the charged particle irradiation unit. It is a vacuum film-forming apparatus provided with the cutter for cutting.

  The invention according to claim 2 of the present invention is the invention according to claim 1, wherein the charged particle irradiation part is generated by hollow cathode discharge and accelerated at a voltage higher than −5.0 kV. It is a vacuum film forming apparatus characterized by comprising a device for irradiating a group.

  According to a third aspect of the present invention, a thin film is formed on the surface of a film substrate that is charged by a charged particle irradiation unit and wound around a metal roll using the vacuum film forming apparatus according to the first or second aspect. After the film is formed, the film on which the thin film is formed is peeled off from the metal roll after being opened to the atmosphere.

  The vacuum film-forming apparatus of the present invention is a vacuum film-forming apparatus having a long film base unwinding portion, a pair of knee rolls for sandwiching the unwound film base from both sides, and a nip roll just below the nip roll. A metal roll for winding the film base, a charged particle irradiation unit for charging the film base at a position close to the upstream surface in the rotation direction of the metal roll under the nip roll, and the metal roll A plurality of film forming sections for forming a thin film on the surface of the film base are provided below, and a cutting cutter for cutting the film base is provided between the nip roll and the charged particle irradiation section. The charged particle irradiator is formed by irradiating one or more charged particle groups generated by hollow cathode discharge and accelerated at a voltage higher than −5.0 kV, and the vacuum Using a membrane device, a method in which a thin film is formed on the surface of a film substrate that is charged by a charged particle irradiation unit and wound around a metal roll, and then released from the atmosphere and then the film on which the thin film has been formed is peeled off from the metal roll. Therefore, the film base material and the metal roll have good adhesion, a thin film can be stably formed on the surface of the film base material, and the film on which the thin film has been formed can be easily peeled off from the metal roll. Further, by providing a plurality of film forming chambers, it is possible to easily and stably form a multilayer thin film on the film base material. It can be widely used in fields that require various functions such as packaging and display.

  A vacuum film forming apparatus and a film forming method using the same according to the present invention will be described in detail below according to embodiments. FIG. 1 is a schematic explanatory view of a vacuum film forming apparatus according to the present invention. In a vacuum chamber (10), an unwinding part (12) of a long film substrate (11) and a plurality of guide rolls (13) A pair of nip rolls (14a, 14b) for sandwiching the film base material (11) from both sides, a metal roll (15) for winding the film base material (11) directly under the nip rolls (14a, 14b), and the nip roll A charged particle irradiation unit (16) for charging the unwound film substrate (11) at a position close to the upstream surface in the rotation direction of the metal roll (15), obliquely below (14a, 14b). A plurality of film forming chambers (17a, 17b) for forming a thin film on the surface of the film base (11) under the metal roll (15), and further, the nip roll (14a) and charged particles Irradiation And a cutter (19) for cutting the film substrate (11) between (16). The film formation chambers (17a, 17b) have opening / closing shutters (18a, 18b), respectively.

  The film substrate (11) is not particularly limited, and examples thereof include polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66, etc.), polystyrene, Films such as ethylene vinyl alcohol, polyvinyl chloride, polyimide, polyvinyl alcohol, polycarbonate, polyether sulfone, acrylic, and cellulose (triacetyl cellulose, diacetyl cellulose, etc.) can be used, and the thickness of the film is preferably 25 to 200 μm.

  The surface of the nip roll (14a, 14b) is made of an insulating material such as urethane rubber.

The metal roll (15) often has a ground potential due to the structure of the vacuum film-forming apparatus. When the charged particles are irradiated onto the film substrate (11), the film substrate (11) is charged, and the metal on the ground potential. Adheres closely to the roll (15). Although the method for generating charged particles in the charged particle irradiation unit (16) is not particularly limited, it is possible to prevent wrinkling at the time of winding around the metal roll (15) by uniformly charging the entire width of the film base (11). Therefore, a method for generating charged particles that can irradiate the entire width of the film substrate (11) is desirable. As an example, a method for charging a wide range using an electron beam will be described. A method of generating plasma by separating electrons from atoms and molecules that exist alone and emitting electrons from them, and a solid surface such as metal There is a method of generating electrons from. Since the former method draws electrons from the plasma space, it has an advantage that a beam can be formed within the drawing range of the space. Therefore, the former method is useful when an electron beam directed to a relatively large area is used.

  In addition, when peeling the film base material (11) closely_contact | adhered to the said metal roll (15), it can carry out easily by making a pressure appropriate. To optimize the pressure, Paschen's law V = f (p × d) (V is the discharge start voltage [volt], f is a function determined by the pressure p [Pa] and the inter-discharge distance d [m]). The voltage V can be reduced. Since the discharge start voltage V is a law that takes a minimum value as a product of the pressure p and the inter-discharge distance d, the discharge start voltage V is determined only by the pressure p if it is assumed that the inter-discharge distance d is constant. . By reducing this discharge start voltage, discharge is easily generated, and electrostatic energy charged in the film base (11) can be released. Moreover, the electrostatic energy which was charged by the influence of the water | moisture content in air etc. can be discharge | released by exposing to air | atmosphere.

  FIG. 2A is a perspective view of an embodiment of the charged particle irradiation unit, which has a slit (21) for irradiating a charged particle group on the side surface of the metal box (20), and an electrode ( (B) is a cross-sectional explanatory view of the charged particle irradiation part of (a), and an electrode (22) made of stainless steel (SUS316) in a metal box (20) made of stainless steel (SUS316). ), And a slit (21) is provided on the surface facing the electrode (22). The gap of the slit (21) is preferably 1.5 mm. With this structure, an electron beam with a large area can be obtained. A gas that is easily discharged, such as argon, is introduced into the metal box (20) as a discharge gas, and plasma is generated in the metal box (20) by applying a high voltage from the DC power source (23) to the electrode (22). Since it is preferable that the electrode (22) for generating plasma has a uniform plasma state in the metal box (20), it is preferable to approximate the size of the side surface of the metal box (20). In addition, it is more preferable that the electrode (22) is hollow so that hollow cathode discharge can be performed, because high-density plasma can be obtained relatively easily. Charged particles can be taken out from the slit (21) and irradiated onto the film substrate to be charged. Charged particles can be broadly classified into electrons with a light mass and heavy ions, and electrons with a light mass are relatively easy to handle when extracting charged particles by voltage acceleration. If it is desired to extract electrons as a beam, a DC voltage that applies a negative potential to the electrode may be applied. In order to emit electrons having momentum from the slit (21), acceleration by a high voltage is required, so that the voltage is preferably −5.0 kv or more. Since the metal box (20) has the same potential as the ground, the electrons are accelerated from the electrode (22) to the metal box (20), and if there is a slit (21) on the surface, the electrons are accelerated from the gap of the slit (21). The extracted electrons can be extracted. An area where electrons can be irradiated is substantially determined by a charged particle irradiation unit including a metal box, an electrode, and a slit. It is preferable that the electrode (22) and the slit (21) having the same size as the surface width of the target film substrate (11) are provided. The electrodes (22) and the metal box (20) are not limited to stainless steel, and metals that can withstand use in vacuum, such as titanium and aluminum, can also be used.

The film forming chambers (17a, 17b) can perform generally known vacuum film forming processes such as vacuum deposition, sputtering, and CVD. For example, the vacuum deposition method is a method of vaporizing a metal, an inorganic compound, an organic compound, etc., and is roughly divided into a resistance heating method, an electron beam heating method, and an induction heating method depending on the heating method, and a process in a vacuum environment. In this regard, reactive vapor deposition, plasma assisted vapor deposition, ion beam assisted vapor deposition, ion plating and the like can be mentioned, but any method may be used. By combining these, an inorganic oxide thin film or the like can be formed relatively easily.

  Sputtering methods include a DC discharge method, a high frequency discharge method, a pulse discharge method, and a magnetron electrode method in which a magnet is disposed on a target electrode, depending on the plasma generation method.

  Further, the CVD method (Chemical Vapor Deposition method) includes a thermal CVD method and a plasma CVD method, but is not limited to these methods, and any method may be used.

  In the various vacuum film forming methods, the physical properties of the film greatly change depending on changes in film pressure, such as gas pressure, gas introduction amount, gas introduction position, ion beam power, plasma power, and gas type. In the case where film formation is performed in the same vacuum chamber, it is preferable to provide vacuum chambers divided for one film formation process and perform vacuum evacuation independently. This is because, for example, the optimum pressure in the vacuum deposition method and the optimum pressure in the sputtering method are often different, so that it is considered necessary to optimize the film forming conditions at the same time.

  A film forming method for forming a thin film using the vacuum film forming apparatus of the present invention will be described below with reference to examples.

Using the vacuum film-forming apparatus shown in FIG. 1, the pressure in the vacuum chamber (10) is reduced to 5.0 × 10 ⁻² Pa or less by a vacuum pump (not shown). Using a PET (polyethylene terephthalate) film having a width of 500 mm and a thickness of 25 μm as the film substrate (11), an electron beam is generated from the charged particle irradiation unit (16) using an 8 kw DC power source (23) at an acceleration voltage of 10 kv. When the PET film was run on a metal roll (15) having a diameter of 750 mm at 2 m / min and wound with an electron beam for more than one turn, the PET film was fixed by a nip roll (14a, 14b) and then a cutter. The PET film was cut using (19). In this state, argon gas was introduced into a film formation chamber (17a) having a copper magnetron sputtering film formation unit having a film formation effective width of 400 mm, and a pressure of 2.0 kW was applied to a copper target having a pressure of 2.0 Pa and an electrode area of 450 mm × 100 mm. Plasma was generated by a direct current power source, and after pre-sputtering, the opening / closing shutter (18a) was opened to start film formation. Similarly, a gas mixed with argon (Ar) gas and oxygen (O ₂ ) gas in a ratio of (Ar) / (O ₂ ) = 4/1 in a film forming chamber (17b) having a plasma CVD film forming unit and hydro A monomer gas obtained by heating methyldisiloxane with a heater at 80 ° C. was introduced, and the pressure was set to 3.5 Pa. The electrode used was made of stainless steel (SUS316) and 400 × 100 mm. A high frequency power source was connected to this electrode, and the frequency was set to 13.56 MHz and the power was set to 1.5 kw. The power supply of the high-frequency power source in the film formation chamber (17b) was started, and a SiO ₂ film was formed on the copper film formed on the PET film by the CVD method and laminated. Subsequently, the supply of high-frequency power in the film formation chamber (17b) was stopped at a point of half a circle from the start of film formation, and a film in which only a copper film was formed was produced. Thereafter, the inside of the vacuum chamber (10) was opened to the atmosphere to take out a film on which a thin film was formed, and a film in which only a copper film and a film in which a SiO ₂ film was laminated on a copper film was obtained.

As a result of measuring the electric resistance value of the film in which the SiO ₂ film was laminated on the copper film obtained in Example 1, the measured value was ² MΩ / cm ² or more. Since the electric resistance value of the film on which only the copper film is formed is 15 Ω / cm ² or less, it was found from the measurement result of the electric resistance that the copper film and the SiO ₂ film were satisfactorily laminated on the film substrate. .

1 is a schematic explanatory diagram of an embodiment of a vacuum film forming apparatus of the present invention. (A) is a perspective view of one Example of a charged particle irradiation part, (b) is sectional explanatory drawing of the charged particle irradiation part of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vacuum tank 11 ... Film base material 12 ... Unwinding part 13 ... Guide roll 14a, 14b ... Nip roll 15 ... Metal roll 16 ... Charged particle irradiation part 17a, 17b ... Deposition chamber 18a, 18b ... Opening / closing shutter 19 ... Cutter 20 ... Metal box 21 ... Slit 22 ... Electrode 23 ... DC power supply

Claims (3)

  In a vacuum film forming apparatus for forming a thin film on a film substrate, a long film substrate unwinding portion, a pair of knee rolls for sandwiching the unwound film substrate from both sides, and a position immediately below the nip roll A metal roll for winding the film base, a charged particle irradiation unit for charging the film base at a position close to the upstream surface in the rotation direction of the metal roll under the nip roll, and the metal roll A plurality of film forming chambers for forming a thin film on the surface of the film base material are provided below, and a cutter for cutting the film base material is provided between the nip roll and the charged particle irradiation unit. A vacuum film forming apparatus characterized by   2. The vacuum film formation according to claim 1, wherein the charged particle irradiation unit is formed by irradiating one or more kinds of charged particle groups generated by hollow cathode discharge and accelerated at a voltage higher than −5.0 kV. apparatus.   A thin film is formed on the surface of a film substrate wound around a metal roll after being charged by a charged particle irradiation unit using the vacuum film forming apparatus according to claim 1 or 2, and then opened to the atmosphere before being thinned. The film-forming method characterized by peeling the film which formed this from the metal roll.