JP2014070233A - Filming apparatus, gas-barrier laminate, and optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-barrier laminate excellent in an oxygen-barrier property and a steam barrier-property by freely setting a plasma density and a voltage to be led in a base material.SOLUTION: A filming apparatus 27 comprises transfer means for transferring a film base material on a roll-to-roll manner and a filming chamber 10 for exposing a film substrate 15 being carried by the transfer means, so that a thin film is formed on the film substrate 15 by a chemical gas phase deposition method using a plasma. Plasma producing means for generating a plasma in the filming chamber 10 is a hollow cathode gun 17 or hollow cathode discharge generating means.

Description

  The present invention relates to a film forming apparatus for manufacturing a thin film laminate on a substrate, a gas barrier laminate produced using the film forming apparatus, and an optical member.

  Food packaging materials, such as pouch materials for retort foods, are laminated packaging materials in which a plastic film as a base material, an aluminum foil as an oxygen and water vapor barrier layer, and a thermoplastic resin film for heat sealing are sequentially laminated. Conventionally, what is printed on the entire surface of the bag to enhance the decoration effect has been widely used. In recent years, with the widespread use of microwave ovens in the home, the market for food packaging materials using packaging films made of flexible plastic films with barrier properties that can be distributed at room temperature and that can be applied to microwave ovens for each packaging material has expanded. doing.

  As a material that satisfies the above characteristics, there is a packaging film in which a flexible plastic film is used as a base material, a metal oxide such as aluminum oxide, magnesium oxide, or silicon oxide is vapor-deposited on this surface, and another film is laminated on the vapor-deposited surface. Proposed. This packaging film is also used as a protective material for packaging materials such as pharmaceuticals, electronic members, and optical members, taking advantage of its excellent disposal property and the ability to confirm the contents from the outside.

  Also, in recent years, regarding electronic paper, organic EL, which is expected as the next generation FPD, and LCD which is widely spread in wide range, in order to achieve the flexibility of these FPDs, or to reduce the weight, cost, glass substrate There is an increasing demand for replacing a glass substrate with a plastic film in order to improve throughput during manufacturing such as cracks. Organic EL is also attracting attention as an alternative illumination method to replace fluorescent lamps. In this case, it is required to use a plastic film for reasons such as weight saving and ensuring safety. On the other hand, apart from making FPD flexible, industrial materials such as solar cell backsheets are often used from the viewpoints of weight reduction, thickness reduction, damage prevention, and the like.

The glass substrate has a gas barrier property required to suppress deterioration of internal elements due to oxygen and water vapor derived from the environment. However, gas barrier films for flexible packaging materials have not reached the barrier level, and industrial materials such as solar battery back sheets to which plastic films can be applied are several times more than barrier films for food packaging materials, electronic paper, organic It is said that a water vapor barrier property of 10 ⁻² g / m ² / day or less is necessary for a display sealing film such as EL. Moreover, a solar cell and a thin film solar cell may be required to have a water vapor barrier property of 1 g / m ² / day or less and a higher barrier property depending on the type of the thin film.

Physical film formation methods (PVD methods) such as induction heating, resistance heating, electron beam evaporation, and sputtering are easy to increase in area and roll-to-roll. It is being considered that high gas barrier properties can be expected. The PVD method is roughly divided into an evaporation method such as an induction heating method, a resistance heating method, and an electron beam evaporation method, and a sputtering method. The vapor deposition method is a method in which the film formation rate is fast but it is difficult to obtain a dense and gas barrier property film. On the other hand, the sputtering method is slow but it is possible to obtain a dense and gas barrier property film. It is. For this reason, in general, gas barrier films for flexible packaging materials often use vapor deposition, and large-area film formation using sputtering is often used for optical film applications that require precise film thickness control. The price per m ^{2 of} the gas barrier film using the sputtering method is higher than that of the vapor deposition method.

  Even if a chemical vapor deposition method (CVD method) is used for the physical film formation method (PVD method), a plastic film having gas barrier properties can be realized. There are various types of chemical vapor deposition methods (CVD methods), such as thermal CVD methods, plasma CVD methods, and catalytic CVD methods. As a method for increasing the area and roll-to-roll, plasma CVD methods are used. It is common. In the plasma CVD method, a power source used as a plasma generation source is generally an AC power source, and in particular, a high frequency power source represented by 13.56 MHz is often used. In general, the higher the frequency, the higher the density of plasma generated, and the easier the decomposition of the monomer gas and reactive gas used. On the other hand, standing waves are more likely to be generated as the frequency is increased, and troubles such as the density of generated plasma becoming non-uniform in space also occur. For this reason, when film-forming with a large area is implemented using plasma CVD method, the countermeasure which avoids a standing wave is needed and becomes complicated. In order to increase the area of a TFT (Thin Film Transistor), a plasma CVD method using a high frequency is used. However, in a roll-to-roll process, an example using a high-frequency power source such as 13.56 MHz is used. Few. As an example of using a plasma CVD method in a roll-to-roll process, the following Patent Document 1 is cited. In this case, the frequency used is several tens of kHz, and the problem of standing waves does not occur. Therefore, the plasma density is not biased in the space, and a uniform thin film can be obtained.

Japanese Patent No. 4414781

  However, in this method, an AC power source is connected to the coating drum, and the coating drum is used as a cathode, thereby generating a discharge and forming a film. However, the cathode fall voltage and the plasma density in the space are uniquely determined, There was a problem that the drawing voltage and plasma density could not be set freely. In addition, standing waves do not occur in the film formation space, but it is difficult to increase the plasma density, and it is difficult for the monomer gas and reactive gas to decompose, and clusters that react in the space are present in the film. There is a problem that it is difficult to obtain high barrier properties when productivity is prioritized as a result. Further, in order to improve the plasma density, it is necessary to take a structure such as separately installing a magnet in the space, and there is a problem that the apparatus becomes complicated and costs increase.

  In view of the above-mentioned problems, the present invention produces a transparent or translucent gas barrier laminate having excellent oxygen barrier properties and water vapor barrier properties by freely setting the plasma density and the drawing voltage to the substrate. Provided is a plasma CVD film forming apparatus that enables this.

As means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that a film substrate is conveyed by a roll-to-roll, and the film substrate being conveyed is exposed by the conveyance device. A film forming chamber for forming a thin film on the film substrate by a chemical vapor deposition method using plasma, wherein the plasma generating means for generating the plasma in the film forming chamber, A monomer gas introducing means for introducing a monomer gas into the film forming chamber; and a reactive gas introducing means for introducing a reactive gas into the film forming chamber, wherein the plasma generating means is a hollow cathode discharge generating means. It is characterized by.
The hollow cathode discharge generating means comprises a cylindrical hollow cathode and two anodes, and one of the anodes is disposed around the hollow cathode, and the other of the other An anode is installed at a position facing the hollow cathode across the film formation chamber.
According to a third aspect of the present invention, the hollow cathode discharge generating means includes a cylindrical hollow cathode and a cylindrical anode installed around the hollow cathode.
According to a fourth aspect of the present invention, the hollow cathode discharge generating means includes a cylindrical hollow cathode and an anode, and the hollow cathode and the anode are located at positions facing each other across the film formation chamber. It is installed.
The invention according to claim 5 is characterized by comprising charged particle incident means for accelerating charged particles in the plasma by an electric field and entering the film substrate.
The invention according to claim 6 is characterized in that the charged particle injection means is an AC power source having a frequency of 1 MHz or less or a pulse power source having a variable duty cycle and pulse width.
The invention according to claim 7 is a gas barrier laminate produced by the film forming apparatus according to any one of claims 1 to 6, wherein the water vapor permeability is 2 g / m ² / day or less. It is characterized by that.
The invention according to claim 8 is a gas barrier laminate manufactured by the film forming apparatus according to any one of claims 1 to 6, wherein the oxygen permeability is 3 cc / m ² / day or less. It is characterized by that.
The invention according to claim 9 is an optical member using the gas barrier laminate manufactured by the film forming apparatus according to any one of claims 1 to 6.

  According to the present invention, it is possible to produce a transparent or translucent gas barrier laminate having excellent oxygen barrier properties and water vapor barrier properties by freely setting the plasma density and the drawing voltage to the substrate. A plasma CVD film forming apparatus, a gas barrier laminate manufactured using the film forming apparatus, and an optical member using the same can be provided.

It is the schematic diagram which showed one Embodiment of the film-forming apparatus of this invention. It is sectional drawing which showed one Embodiment of the hollow cathode gun of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of a film forming apparatus of the present invention. The film forming apparatus 27 includes a film forming chamber 10 and a take-up chamber 11, and includes a transport unit that transports the film base material 15 in a roll-to-roll manner within the film forming apparatus 27. Means for transporting the film substrate in a roll-to-roll manner includes an unwinding roller 12, a winding roller 13, and a coating drum 14. The film substrate 15 is unwound from the unwinding roller 12, and is wound around the winding roller 13 via the coating drum 14. At this time, the coating drum 14 forms a film on the film substrate 15 by the plasma CVD method. That is, the film forming apparatus 27 includes a transport unit that transports the film base material in a roll-to-roll manner, and a film forming chamber 10 to which the film base material being transported by the transport unit is exposed. A thin film is formed on the film substrate by vapor deposition.

  The film substrate 15 is not particularly limited, and a known one can be used. For example, polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66, etc.), polystyrene, ethylene vinyl alcohol, polyvinyl chloride, polyimide, polyvinyl alcohol, Polycarbonate, polyethersulfone, acrylic, cellulose-based (triacetyl cellulose, diacetyl cellulose, etc.) and the like are exemplified, but not particularly limited. In practice, it is desirable to make appropriate selections depending on the application and the required physical properties, but this is not a limited example, but for packaging of medical supplies, medicines, foods, etc., polyethylene terephthalate, polypropylene, nylon (registered trademark), etc. cost For the packaging that protects contents that are extremely hated of moisture such as electronic members and optical members, base materials having high gas barrier properties such as polyethylene naphthalate, polyimides, polyethersulfone, etc. are used. It is desirable. Moreover, although the base film thickness is not limited, about 6 to 200 μm is easy to use depending on the application.

  In order to perform film formation by plasma CVD, a hollow cathode gun 17 (plasma generating means) using hollow cathode discharge is installed as a source of plasma 16, and an internal electrode 18 or an external electrode 19 is installed as an anode. Has been. The hollow cathode gun 17 is connected to a hollow cathode discharge DC power source 22 for generating a hollow cathode discharge.

In hollow cathode discharge, electrons accelerated by a sheath voltage in a cylindrical hollow cathode move in the hollow cathode and decelerate in reverse by the sheath voltage of the hollow cathode. It refers to high density plasma that is accelerated by the sheath voltage and is repeatedly ionized by moving through the hollow cathode. The introduction of the gas from the hollow cathode into the film forming chamber 10 is performed because the generated high-density plasma is drawn out toward the film forming chamber 10 because there is a pressure difference between the film forming chamber 10 and the inside of the hollow cathode. Is called. The gas introduced from the hollow cathode can be stably discharged for a long time without inert gas such as N ₂ including inert gases such as Ar, He, Ne and other inert gases. Although it is preferable, it is not limited to this.

  The internal electrode 18 is an anode for the hollow cathode, is installed inside the hollow cathode gun 17, and has a mechanism for generating a hollow cathode discharge inside the hollow cathode gun 17.

  FIG. 2 is a sectional view showing an embodiment of the hollow cathode gun 17 of the present invention. The hollow cathode gun 17 includes a hollow cathode 28 and an anode 29 positioned around the hollow cathode 28, and high density plasma is generated inside the hollow cathode 28. The internal electrode 18 corresponds to the anode 29.

  Further, since the discharge may become unstable when the internal electrode 18 is contaminated by the film forming material, a structure such as providing an adhesion preventing plate may be provided so that the internal electrode 18 is not easily contaminated.

  On the other hand, the external electrode 19 is an anode for the hollow cathode, like the internal electrode 18, and may be positioned outside the hollow cathode gun 17, but faces the hollow cathode gun 17 across the coating drum 14 as shown in FIG. It is preferable to be installed at a position.

  When the external electrode 19 is used as an anode, the plasma 16 satisfies the bipolar diffusion phenomenon as shown in FIG. 1, and discharge occurs between the hollow cathode 28 and the external electrode 19. Whether to use the internal electrode 18 or the external electrode 19 can be switched by the switch 23 and the switch 24.

  That is, the hollow cathode gun 17 which is a hollow cathode discharge generating means includes a cylindrical hollow cathode 28 and two anodes, and one anode 29 (internal electrode 18) is disposed around the hollow cathode 28, while the other The anode (external electrode 19) is placed at a position facing the hollow cathode 28 with the film formation chamber 10 in between. Note that only one anode of the hollow cathode discharge generating means may be provided. That is, the hollow cathode discharge generating means may be composed of a cylindrical hollow cathode 28 and a cylindrical anode 29 installed around the hollow cathode 28, or the cylindrical hollow cathode 28 and the anode ( The hollow cathode 28 and the anode (external electrode 19) may be installed at positions facing each other across the film forming chamber 10.

  In order to perform film formation by plasma CVD, it is necessary to introduce a monomer and a reactive gas into the film formation chamber 10. A monomer gas introduction mechanism 20 (monomer gas introduction means) and a reactive gas introduction mechanism 21 (reactive gas introduction means) are installed in the film forming chamber 10, respectively. For example, the introduction mechanism may be introduced from a single source instead of a plurality according to the required performance such as water vapor permeability and oxidation permeability, and the required film formation rate. The gases introduced from the monomer gas introduction mechanism 20 and the reactive gas introduction mechanism 21 are dissociated, ionized, and radicalized by the plasma 16 generated in the film forming chamber 10. As a result, a film in which the monomer gas component reacts with the reactive gas is formed on the film substrate 15 that is transporting the coating drum 14.

  A plurality of hollow cathode guns 17 may be installed in the film forming apparatus depending on the size of the film base 15 in the width direction. When the external electrode 19 is used as an anode, a plurality of hollow cathode guns 17 are provided according to the number of hollow cathode guns 17. May be installed. Further, a magnetic field such as a converging magnetic field may be provided to the hollow cathode gun 17 and the external electrode 19.

  As for the discharge conditions of the plasma 16, the higher the current value, from several A to several hundred A per hollow cathode, the higher the plasma density, and the more preferable is the point of promoting dissociation, ionization, and radicalization. However, since an unreacted component of the monomer gas remains in the film, there is an effect that the stress of the film is relieved. Therefore, the current value may be set depending on the desired effect. Similarly, it is possible to introduce a large amount of monomer gas and reactive gas in a state where the current value is high to increase the film formation rate as appropriate.

  Further, the film forming apparatus of the present invention includes means (charged particle incident means) for accelerating charged particles in the plasma 16 by an electric field and entering the film substrate 15. An electric field acceleration power supply 25 is connected to the coating drum 14 so that charged particles in the plasma can be accelerated by the electric field and incident on the film substrate 15 with high kinetic energy.

  The electric field acceleration power source 25 (charged particle injection means) may be any one of a DC power source, a pulse power source, and an AC power source. For example, an AC power source having a frequency of 1 MHz or less or a pulse power source having a variable duty cycle and pulse width may be used. desirable. When using a pulse power supply, it is necessary to appropriately determine the pulse width and the duty cycle. When using an AC power supply, it is necessary to appropriately determine the frequency in combination with the film formation rate. Since a plastic substrate is used as the film substrate, it may be necessary to perform charging relaxation when an insulator is formed. Therefore, either a pulse power source or an AC power source is desirable. When an AC power supply is used, in order to apply a negative voltage to the coating drum 14, a capacitor 26 is inserted between the coating drum 14 and the electrolytic acceleration power supply 25 to induce a negative voltage in the coating drum 14.

  The film forming apparatus of the present invention is introduced from the hollow cathode gun 17 at the same time that the film constituent particles introduced from the monomer gas introduction mechanism 20 and the reactive gas introduction mechanism 21 are dissociated, ionized and excited in the plasma 16. Since the ions of the inert gas can be accelerated by the electric field and can be incident on the film substrate 15, an assist effect is obtained, so that a denser film can be formed.

In addition, the gas barrier laminate formed by the film forming apparatus of the present invention preferably has a water vapor permeability of 2 g / m ² / day or less. The film forming apparatus of the present invention can freely set the plasma density by changing the monomer gas introduction amount, the reactive gas introduction amount, the flow rate of the gas introduced from the hollow cathode, and the current value of the hollow cathode, and the film formation rate. Therefore, by setting the water vapor permeability within a specific range, a gas barrier laminate having excellent water vapor barrier properties can be produced.

Furthermore, the gas barrier laminate formed by the film forming apparatus of the present invention preferably has an oxygen permeability of 1 cc / m ² / day or less. The film forming apparatus of the present invention can freely set the plasma density by changing the monomer gas introduction amount, the reactive gas introduction amount, the flow rate of the gas introduced from the hollow cathode, and the current value of the hollow cathode, and the film formation rate. Therefore, by setting the water vapor permeability within a specific range, a gas barrier laminate having excellent water vapor barrier properties can be produced.

  Specific examples of the present invention are shown below.

<Example 1>
Using the film forming apparatus shown in FIG. 1, 200 sccm of HMDSO is introduced from the monomer gas introduction mechanism 20 and 200 sccm of oxygen gas is introduced from the reactive gas introduction mechanism 21, and a PET film having a thickness of 12 μm is used as the film substrate 15. The silicon oxide film having a physical film thickness of 20 nm was formed on the film substrate. At this time, argon gas was flowed through the hollow cathode gun 17 at 150 sccm, and a 27 V, 60 A discharge was generated between the hollow cathode and the counter electrode 18 by using the hollow cathode discharge DC power source 22.

<Example 2>
Using the film forming apparatus shown in FIG. 1, 200 sccm of HMDSO is introduced from the monomer gas introduction mechanism 20 and 200 sccm of oxygen gas is introduced from the reactive gas introduction mechanism 21, and a PET film having a thickness of 12 μm is used as the film substrate 15. The silicon oxide film having a physical film thickness of 20 nm was formed on the film substrate. At this time, argon gas was passed through the hollow cathode gun 17 at 150 sccm, and a 40 V, 60 A discharge was generated between the hollow cathode and the counter electrode 19 using the hollow cathode discharge DC power source 22.

<Example 3>
Using the film forming apparatus shown in FIG. 1, 200 sccm of HMDSO is introduced from the monomer gas introduction mechanism 20 and 200 sccm of oxygen gas is introduced from the reactive gas introduction mechanism 21, and a PET film having a thickness of 12 μm is used as the film substrate 15. The silicon oxide film having a physical film thickness of 20 nm was formed on the film substrate. At this time, argon gas was passed through the hollow cathode gun 17 at 150 sccm, and a 38 V, 60 A discharge was generated between the hollow cathode and the counter electrode 19 by using the hollow cathode discharge DC power source 22. Further, an AC power supply with a frequency of 40 kHz was installed as the electric field acceleration power supply 25, the voltage was set to 150 V, and charged particles in the plasma were drawn.

<Comparative Example 1>
Using the film forming apparatus shown in FIG. 1, 200 sccm of HMDSO is introduced from the monomer gas introduction mechanism 20 and 200 sccm of oxygen gas is introduced from the reactive gas introduction mechanism 21, and a PET film having a thickness of 12 μm is used as the film substrate 15. 12 was passed toward the take-up roller 13. At this time, 10 kW was applied to the electric field acceleration power supply 25 which is an AC power supply having a frequency of 40 kHz to generate plasma. Thereby, a silicon oxide film having a physical thickness of 20 nm was formed on the film substrate.

  About the created sample, water vapor permeability and oxygen permeability were measured by the following methods.

(Evaluation method)
The water vapor transmission rate was measured by the MOCON method. The measuring instrument used was measured by MOCON PERMATRAN (registered trademark) 3/33 at 40 ° C. and 90% Rh, and the oxygen permeability was measured by MOCON OX-TRAN (registered trademark) 2/20 at 23 ° C. and 0% Rh. Measured at

  Table 1 shows the water vapor transmission rate and oxygen transmission rate of the samples prepared in Example 1, Example 2, Example 3, and Comparative Example.

  From the results shown in Table 1, when the film forming apparatus of the present invention was used, results showing high water vapor barrier properties and oxygen barrier properties were obtained, and results were obtained in which the gas barrier by electric field acceleration was further improved.

  The film forming apparatus of the present invention is suitable for producing an oxygen and water vapor barrier laminate (gas barrier laminate), and the oxygen and water vapor barrier laminate produced using the film forming apparatus of the present invention is In addition to the barrier member, it is also used for optical members such as optical films and optical functional filters.

DESCRIPTION OF SYMBOLS 10 ... Film-forming chamber 11 ... Winding chamber 12 ... Unwinding roller 13 ... Winding roller 14 ... Coating drum 15 ... Film base material 16 ... Plasma 17 ... Hollow cathode gun (plasma generating means)
18 ... Internal electrode 19 ... External electrode 20 ... Monomer gas introduction mechanism (monomer gas introduction means)
21 ... Reactive gas introduction mechanism (reactive gas introduction means)
22 ... DC power source for hollow cathode discharge 23, 24 ... Switch 25 ... Power source for electric field acceleration 26 ... Capacitor 27 ... Film-forming device 28 ... Hollow cathode 29 ... Anode

Claims (9)

A film transporting means for transporting the film base material in a roll-to-roll manner; and a film forming chamber to which the film base material being transported by the transporting means is exposed. The film is formed by chemical vapor deposition using plasma. A film forming apparatus for forming a thin film on a substrate,
Plasma generating means for generating the plasma in the film forming chamber;
Monomer gas introduction means for introducing monomer gas into the film forming chamber;
Reactive gas introduction means for introducing a reactive gas into the film formation chamber,
The film forming apparatus, wherein the plasma generating means is a hollow cathode discharge generating means.   The hollow cathode discharge generating means includes a cylindrical hollow cathode and two anodes, one of the anodes is provided around the hollow cathode, and the other anode is sandwiched between the film formation chambers and the hollow cathode. The film forming apparatus according to claim 1, wherein the film forming apparatus is installed at a position facing the cathode.   The film forming apparatus according to claim 1, wherein the hollow cathode discharge generating unit includes a cylindrical hollow cathode and a cylindrical anode installed around the hollow cathode. The hollow cathode discharge generating means comprises a cylindrical hollow cathode and an anode,
The film forming apparatus according to claim 1, wherein the hollow cathode and the anode are installed at positions facing each other across the film forming chamber.   5. The film forming apparatus according to claim 1, further comprising charged particle incident means for accelerating charged particles in the plasma by an electric field and entering the film base material.   6. The film forming apparatus according to claim 5, wherein the charged particle incident means is an AC power source having a frequency of 1 MHz or less or a pulse power source having a variable duty cycle and pulse width. A gas barrier laminate produced by the film forming apparatus according to any one of claims 1 to 6, wherein a water vapor permeability is 2 g / m ² / day or less. 7. A gas barrier laminate produced by the film forming apparatus according to claim 1, wherein the oxygen permeability is 3 cc / m ² / day or less.   The optical member using the gas-barrier laminated body manufactured with the film-forming apparatus in any one of Claim 1 to 6.

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