JP2005200710A - Method of depositing thin film, thin film produced thereby and transparent plastic film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of depositing a thin film by a plasma CVD (chemical vapor deposition) method at a high film deposition yield and a high film deposition rate according to CVD conditions where a film deposition yield is high and a film deposition rate is high, to provide a thin film having a high gas barrier produced thereby, and to provide a transparent plastic film. <P>SOLUTION: In the thin film deposition method by an atmospheric pressure plasma CVD process, a gaseous starting material comprising the raw material for a thin film is passed through a first plasma discharge space and is thereafter passed through a second plasma discharge space to deposit a thin film on a base material in the second plasma discharge space, electric field intensity E1 applied to the first plasma discharge space and electric field intensity E2 applied to the second plasma discharge space satisfy the inequality (1) of E2≥E1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for forming a thin film, and the thin film and transparent plastic film produced thereby.

  Conventionally, as a substrate for an electronic display element such as a liquid crystal display element, an organic EL display element, a plasma display or an electronic paper, an electron optical element substrate such as a CCD or CMOS sensor, or a substrate for a solar cell, thermal stability, transparency Glass has been used because of its high water vapor permeability and low water vapor permeability. However, with the recent popularization of mobile phones or portable information terminals, there has been a demand for lightweight substrates that are highly flexible and hard to break, compared to glass that is easily broken and relatively heavy.

  However, since the plastic substrate has gas permeability, it is difficult to apply to a device whose performance deteriorates due to deterioration due to moisture or oxygen, such as an organic electroluminescence display device. It was a problem to do.

  In order to suppress such permeation of water vapor and oxygen, it is known to provide a film (gas barrier film) that suppresses various gases from permeating the plastic substrate. Examples of such a layer include a silicon oxide film, nitriding Silicon film, silicon oxynitride film, silicon carbide film, aluminum oxide film, aluminum oxynitride film, titanium oxide film, zirconium oxide film, indium oxide film, magnesium oxide, boron nitride film, carbon nitride film, diamond-like carbon film, fluorine Magnesium fluoride and aluminum fluoride films are known.

  As a method for forming a gas barrier film made of an inorganic material as described above on a plastic film, it can be roughly divided into a physical vapor deposition method (PVD method), a chemical vapor deposition method (CVD method), a coating method ( There are three types: sol-gel method.

  The PVD method can be further divided into a vacuum deposition method, a sputtering method, an ion plating method, and the like. The vacuum deposition method is a method in which ceramics are heated under high vacuum by a method such as electron beam irradiation, resistance heating, induction heating, and the like, and volatilized fine ceramic clusters are deposited on a substrate. The sputtering method is a technique in which ions of a rare gas such as argon are incident on a ceramic target at high speed under high vacuum, and fine ceramic clusters ejected by elastic collision are deposited on the substrate. The ion plating method is a method in which fine clusters of ceramics charged under a high vacuum are generated and deposited on a substrate charged to a reverse charge. All of these PVD methods require high vacuum conditions, and the material constituting the thin film linearly flies from the ceramic target, resulting in poor coverage, and regular deposition on the film, resulting in cracks. There is a problem that the film tends to occur.

  The CVD method is a method in which a compound containing raw materials constituting a thin film is volatilized in the vicinity of a base material, and then a chemical reaction is induced by heat, light, plasma, etc., and the generated ceramic is deposited on the base material. . Depending on the method of applying energy that causes a chemical reaction to the raw material compound, it is classified into thermal CVD, photo CVD, plasma CVD, etc., respectively.

  In thermal CVD, a temperature of 500 ° C. or higher is usually required, and since it is difficult to design a raw material compound in photo-CVD, film formation on a plastic substrate is mostly performed by plasma CVD.

  In the CVD method, chemically active compounds such as radicals are generated, so the adhesiveness with the base material is high, and since the chemical reaction occurs due to collision between molecules, there is no direction to the material that composes the thin film, A highly coatable film is obtained. However, in many cases, there is a problem that an organic metal compound as a raw material is expensive.

  In addition, the sol-gel method is a technique for obtaining a ceramic thin film by hydrolyzing an organometallic compound dissolved in a solvent, applying it to a substrate, and drying it. However, the gas barrier property is low because micro voids through which the solvent that volatilizes pass are formed, and in order to eliminate such micro voids, it is necessary to sinter at a high temperature, and the gas barrier property is high on the plastic substrate. It is difficult to obtain a film.

  Therefore, the methods capable of forming a ceramic thin film having a high gas barrier property on a plastic film are practically limited to the PVD method and the plasma CVD method. Furthermore, the plasma CVD method is the most preferable means in consideration of the obtained film quality. Furthermore, in recent years, it has been clarified that the plasma CVD method can be carried out even under atmospheric pressure, and the plasma CVD method is a preferable means in terms of productivity.

  However, as described above, since the raw material that can be used for the plasma CVD method is an expensive organometallic compound, there is a great cost problem.

On the other hand, as an improvement study of the plasma discharge apparatus, as disclosed in Patent Document 1, a combination of a plasma jet electrode and a parallel plate electrode is also disclosed. However, the invention described in Patent Document 1 is a plasma CVD apparatus for forming a film on a thick substrate or a substrate having a complicated shape under atmospheric pressure, from the viewpoint of increasing the film formation yield. Therefore, there is no description related to Patent Document 1 described above.
JP 2003-41372 A

  In order to solve the above problems, the inventors of the present invention diligently studied and found that the yield in the plasma CVD method (the amount of film formation relative to the consumption amount of the raw material compound) is low, which is half of the raw material used. It was found that the above was discharged out of the film forming chamber without being formed into a film.

  Therefore, an object of the present invention is to find a plasma CVD condition with a high film forming yield and a high film forming speed, and thereby a method for forming a thin film by a plasma CVD method with a high film forming yield and a high film forming speed. The object is to provide a thin film and a transparent plastic film having a high gas barrier property.

  The inventors of the present invention have been working to improve the yield in the plasma CVD method, improve the film forming speed, and solve the cost problem in the plasma CVD method. And found out that the object of the present invention can be achieved.

  That is, the object of the present invention is achieved by adopting the following configuration.

(Claim 1)
An atmospheric pressure plasma CVD in which a source gas containing a thin film source is introduced into the second plasma discharge space after passing through the first plasma discharge space and forms a thin film on the substrate in the second plasma discharge space A method of forming a thin film by a method,
A method of forming a thin film, wherein the electric field intensity E1 applied to the first plasma discharge space and the electric field intensity E2 applied to the second plasma discharge space satisfy the following formula (1):

E2 ≧ E1 (1)
(Claim 2)
The temperature T1 of the pair of electrodes forming the first plasma discharge space and the temperature T2 of the pair of electrodes forming the second plasma discharge space satisfy the following formula (2): The method for forming a thin film according to claim 1.

T2 ≧ T1 (2)
(Claim 3)
A first inert gas, a raw material gas, and a first decomposition gas are introduced into the first plasma discharge space, and a gas passing through the first plasma discharge space, a first gas, and the like are introduced into the second plasma discharge space. 2. The method for forming a thin film according to claim 1, wherein two inert gases and a second cracked gas are introduced.

(Claim 4)
A gas passing through the first plasma discharge space is introduced onto the substrate in the second plasma discharge space, and a second inert gas and a second gas are introduced above the gas passing through the first plasma discharge space. The method for forming a thin film according to claim 1, wherein the decomposition gas is introduced.

(Claim 5)
5. The method for forming a thin film according to claim 1, wherein the first cracked gas is a reducing gas and the second cracked gas is an oxidizing gas. 6.

(Claim 6)
6. The thin film forming method according to claim 1, wherein the first plasma discharge space and the second plasma discharge space are continuous.

(Claim 7)
7. The method for forming a thin film according to claim 1, wherein both the first plasma discharge space and the second plasma discharge space are under atmospheric pressure or a pressure in the vicinity of atmospheric pressure.

(Claim 8)
The high-frequency voltage applied to the electrode is in the range of 1 kHz to 2500 MHz, and the supplied power is in the range of 1 to 50 W / cm ^2. Method for forming a thin film.

(Claim 9)
9. The high frequency voltage according to claim 1, wherein an alternating voltage having a frequency in a range of 1 kHz to 1 MHz is superimposed on an alternating voltage having a frequency of 1 MHz to 2500 MHz. Method for forming a thin film.

(Claim 10)
The thin film formed by the formation method of the thin film of any one of Claims 1-9 is an inorganic oxide thin film, The thin film characterized by the above-mentioned.

(Claim 11)
A thin film formed by the method for forming a thin film according to claim 1, wherein the thin film is a silicon oxide thin film.

(Claim 12)
It is a thin film formed with the formation method of the thin film of any one of Claims 1-9, Comprising: The water-vapor-permeation rate of this thin film is 1.0 g / m < ² > / d or less, It is characterized by the above-mentioned. Thin film.

(Claim 13)
A thin film was formed into a film by forming a thin film according to any one of claims 1 to 9, the oxygen permeability of the thin film is 1.0cc / m ² /d(1.0ml/m ² / d ) A thin film characterized by:

(Claim 14)
A transparent plastic film, wherein the thin film formed by the method for forming a thin film according to any one of claims 1 to 9 is formed on a transparent plastic film substrate.

(Claim 15)
The transparent plastic film according to claim 14, wherein the glass transition temperature of the transparent plastic film substrate is 180 ° C or higher.

(Claim 16)
The transparent plastic film according to claim 14 or 15, wherein the transparent plastic film substrate is a plastic film mainly composed of cellulose ester.

  According to the present invention, a plasma CVD condition having a high film forming yield and a high film forming speed has been found, whereby a method for forming a thin film by a plasma CVD method having a high film forming yield and a high film forming speed, It is possible to provide a thin film and a transparent plastic film having a high gas barrier property.

  Hereinafter, the present invention will be described in detail.

  In the plasma CVD method, the most common electrode is a parallel plate type electrode as shown in FIG. The base material (film) F to be formed is placed on the ground electrode 10 covered with the dielectric 11, and the applied electrodes 12A and 12B are placed in parallel with a distance b1 between the slits thereon to form the slit B1. doing.

  The electrodes 12A and 12B are covered with dielectrics 13A and 13B. 12A and 12B are installed in parallel with a distance a1 between the slits to form a slit A1. A raw material gas is supplied to the slit A1 from the gas ejection part 15 from the outside through the electrode support member 14. The supplied source gas is supplied through the slit A1 to the slit B1 serving as a plasma discharge space by the application electrodes 12A and 12B and the ground electrode 10. The source gas is decomposed in the plasma discharge space and deposited on the substrate F. Since the substrate F is exposed to the plasma discharge space, it cannot be used for a substrate having low plasma resistance.

  An electrode configuration used for forming a film on a substrate having low plasma resistance is a plasma jet electrode whose configuration is shown in FIG. The base material F to be formed is placed on the support member 20 covered with the dielectric 21, and is placed with a distance b2 between the slits to form a slit B2. An application electrode 22 and a ground electrode 23 are installed in parallel on the support member 20, and the electrodes 22 and 23 are covered with dielectrics 24 and 25, respectively. The application electrode 22 and the ground electrode 23 are disposed in parallel with a distance a2 between the slits, and form a slit A2. Supplyed from the gas ejection part 27 from the outside of the electrode support member 26, the slit A2 between the electrode 22 and the ground electrode 23 is a plasma discharge space, and the source gas is decomposed in the plasma discharge space, and the substrate F Deposit. Since the substrate F is not directly exposed to the plasma discharge space, a ceramic thin film can be formed on a substrate having low plasma resistance. However, since the film-forming area where the substrate F and the plasma discharge space containing the raw material are in contact is small, the film-forming speed is slow and the film-forming yield is generally low.

  According to the measurement by the present inventors, for example, the film formation yield of tetraethoxysilane (TEOS) is about 20% for the parallel plate type electrode of FIG. 1 and about 5% for the plasma jet type electrode of FIG. It was found that most of the raw material gas was discharged on the base material F without depositing, regardless of the degree.

The exhausted gas was collected and analyzed by TOF-SIMS, and as a result, it was suggested that many components having groups such as undecomposed Si—OCH ₂ CH ₃ remained. These results show that the decomposition of the raw material gas is insufficient in the one-stage plasma discharge space, and as a result, there are many particles that are released to the outside of the plasma discharge space before growing into large particles that can be deposited. It was inferred that the film yield was low.

  Accordingly, the present inventors have studied a configuration in which the parallel plate electrode and the plasma jet electrode are combined. A method of combining a plasma jet electrode and a parallel plate electrode is also disclosed in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2003-41372).

  The publication is a plasma CVD apparatus for forming a film on a thick substrate or a substrate having a complicated shape under atmospheric pressure, and there is no description about the film formation yield. In addition, the publication does not describe the electric field strengths of the first plasma discharge space and the second plasma discharge space, or the decomposition gas conditions.

Furthermore, the relationship between the electric field strengths in the examples of the publication is as follows: electric field strength E1 (50 kV / cm) of the first plasma discharge space (10 kHz, 5 kV, gap between electrodes 1 mm)> second plasma discharge space (13.56 MHz, Electric field intensity E2 (approximately 10 kV / cm ² ) of 10 W / cm ² and a gap between electrodes of 5 mm. In the electrode having such a configuration, although decomposition of the raw material compound is promoted, a large amount of silicon oxide fine particles are discharged without depositing on the base material, and there is no significant difference in film formation yield.

  If the raw material gas is decomposed in the two-stage plasma discharge space, the gas released to the outside of the film forming system can be reduced without being decomposed, and the conversion rate of the raw material gas is clearly higher than that of the single-stage decomposition. It has improved. Therefore, it was investigated whether the electrode configuration described in the above-mentioned patent document could be improved and the adhesion rate of depositing silicon oxide fine particles on the substrate could be improved. This is because it is considered possible to improve the film forming yield.

  The present invention has attempted to improve the electrode, and as a result, has found that the film-forming yield can be improved by a two-stage decomposition method satisfying the formula (1).

E2 ≧ E1 (1)
(E1 is the electric field strength applied to the first plasma discharge space, E2 is the electric field strength applied to the second plasma discharge space)
The reason why the film forming yield (adhesion rate) is improved by the above conditions is not clear, but is estimated as follows.

  The source gas is introduced into the second plasma discharge space when the organic group is decomposed in the first plasma discharge space and becomes active. In the second plasma discharge space, there is a substrate film or a substrate film on which silicon oxide has already been deposited to some extent, and therefore there is a site in the excited state on the substrate surface or silicon oxide on the substrate surface. Since the excitation site density on the surface of the substrate has a relationship of E2 ≧ E1, it is higher than the excitation particle density of the silicon oxide fine particles excited in the first plasma discharge space. It is estimated that a silicon oxide film is deposited on the base material and silicon oxide fine particles released to the outside of the second plasma discharge space are greatly suppressed.

  Further, in order to increase the excited state of the second plasma discharge space from the excited state of the first plasma discharge space, in addition to the electric field strength, the electrode temperature T2 of the pair of electrodes forming the second plasma discharge space is: The temperature is preferably higher than the electrode temperature T1 of the pair of electrodes forming the first plasma discharge space forming the plasma discharge space. That is, it is preferable to satisfy the formula (2).

T2 ≧ T1 (2)
(T1 and T1 ′ are the temperatures of the pair of electrodes that form the first plasma discharge space, and T2 and T2 ′ are the temperatures of the pair of electrodes that form the second plasma discharge space)
Furthermore, in order to increase the recombination probability with the source gas-derived silicon oxide fine particles on the surface of the base material, the source gas passing through the first plasma discharge space is preferably present at a higher concentration at a position close to the base material. . Thus, in order to form the concentration gradient of the source gas in the second plasma discharge space, the source gas that has passed through the first plasma discharge space is introduced at a position close to the base material and is far from the base material. It is effective to introduce a discharge gas containing no source gas at the position.

  If carbon remains in the film, a dangling bond is formed in the silicon oxide film and the gas barrier property is lowered. However, the excitation intensity of the second plasma discharge space is higher than the excitation intensity of the first plasma discharge space. The carbon derived from the source gas is less likely to be mixed into the silicon oxide film, and the gas barrier property can be improved.

From the viewpoint of reducing the carbon content, the discharge gas introduced into the plasma discharge space preferably contains a decomposition gas. Decomposed gas is an additive gas that can remove organic components from the silicon oxide film by reducing or oxidizing organic groups contained in the raw material to decompose them into highly volatile low molecules such as CH ₄ and CO _2. Refers to that.

  Such cracked gases include hydrogen, water, ammonia, methane, hydrogen sulfide and other reducing gases that generate hydrogen atoms, oxygen, ozone, nitrous oxide, nitrogen monoxide, nitrogen dioxide, and monoxide. Examples thereof include oxidizing gases that generate oxygen atoms such as carbon, carbon dioxide, and sulfur dioxide. As the decomposition gas, either a reducing gas or an oxidizing gas can be used. However, since each has a different reactivity, the first decomposing gas is introduced into the first plasma discharge space, and the second plasma discharge space is used. Can add a second decomposable gas to obtain a silicon oxide film having a low carbon content.

  In addition, since a hydrogen atom is a monovalent atom and an oxygen atom is a divalent atom, not only the decomposability of an organic group but also the polymerizability of a silicon-containing molecule is very high. As a result, the oxidizing gas has a high growth rate of silicon oxide fine particles and tends to be relatively large particles in the gas phase. A film in which relatively large particles are deposited is not preferable because it tends to be coarse and has a low gas barrier property. Therefore, it is preferable to use a reducing gas as the first decomposable gas and an oxidizing gas as the second decomposable gas. By adopting such a structure, it is possible to suppress the formation of coarse particles in the gas phase before depositing on the substrate, and to form dangling bonds in the silicon oxide film deposited on the substrate. In addition, silanol groups, particularly silanol groups that are difficult to remove with a reducing gas, can be removed with an oxidizing gas, and higher gas barrier properties can be obtained.

  Moreover, it is preferable that the 1st plasma discharge space and the 2nd plasma discharge space are continuing from a viewpoint that a coarse particle is not formed. If a non-excited state space is passed between the first plasma discharge space and the second plasma discharge space, recombination / aggregation of silicon oxide fine particles occurs in the non-excited state space, which tends to be coarse particles. It is not preferable. Even if a non-excited state space is generated between the first plasma discharge space and the second plasma discharge space due to the convenience of the plasma CVD apparatus, the first plasma discharge space and the second plasma discharge space are as much as possible. It is preferable that they are close to each other.

  Of the plasma CVD methods, the atmospheric pressure plasma CVD method is preferable. The normal plasma CVD method is performed under a vacuum of about 10 to 1000 Pa. However, since the atmospheric pressure plasma CVD method can form a film under an atmospheric pressure of about 100 kPa, a large-scale vacuum facility is not required and the productivity is high. Not only that, the density of the excited gas is high, so that the film forming speed is high.

  When plasma discharge is performed under atmospheric pressure, it is necessary to apply a high voltage and high power of a certain level or more because of the large amount of gas molecules to be excited. In addition, it is preferable to apply an alternating electric field having a different frequency in a superimposed manner because various molecules contained in the source gas can be excited more efficiently.

  Hereinafter, an apparatus for forming a metal oxide thin film of the present invention will be described in detail with reference to the accompanying drawings. In addition, in this invention, the atmospheric pressure vicinity represents the pressure of 20 kPa-110 kPa, More preferably, it is 93 kPa-104 kPa.

  FIG. 3 is a configuration diagram of the simplest electrode structure of an electrode for plasma CVD having a first plasma discharge space and a second plasma discharge space.

  The plasma CVD apparatus of FIG. 3 is similar in appearance to the parallel plate electrode of FIG. 1, but the upper electrode is actually composed of four electrodes. The application electrode 32A is bonded to the application electrode 33A with the insulator 34A interposed therebetween, and the dielectric 35A covers the 32A, 33A, and 34A together. The ground electrode 32B is bonded to the application electrode 33B with the insulator 34B interposed therebetween, and the dielectric 35B covers the 32B, 33B, and 34B together. The lower ground electrode 30 is covered with a dielectric 31, and a base film F is placed thereon. A hollow portion exists in the electrodes 30, 32A, 32B, 33A, 33B so that a liquid for adjusting the temperature can circulate, and the electrode temperature can be set independently.

  The application electrode 32A and the ground electrode 32B face each other in parallel with a distance between the slits a3 to form a slit A3. The slit A3 forms a first plasma discharge space. The ground electrode 30 and the electrodes 33A and 33B are installed in parallel with a distance b3 between the slits to form a slit B3, and this slit B3 forms a second plasma discharge space. Since the electrodes 32A, 33A, 33B are all connected to the same power supply RF, in order to change the electric field applied to the first plasma discharge space and the second plasma discharge space, the ground constituting the plasma discharge space This is performed by controlling the distances a3 and b3 between the electrodes. In order to satisfy the above condition of E2 ≧ E1, a3 ≧ b3 may be satisfied.

  The source gas is supplied from the outside of the electrode support member 36 to the gas ejection portion 37 and is supplied to the first plasma discharge space A3. The supplied source gas is decomposed in the first plasma discharge space, continuously supplied to the second plasma discharge space B3, and deposited on the substrate F.

  FIG. 4 is a diagram showing an example of an electrode configuration that can be supplied with a high concentration of source gas in the vicinity of the substrate in the second plasma discharge space.

  The application electrode 42A forming the first plasma discharge space is integrated with the insulator 44A, and 42A and 44A are collectively covered with the dielectric 45A. The ground electrode 42B forming the first plasma discharge space is integrated with the insulator 43B, and 42B and 44B are collectively covered with the dielectric 45B. The electrode and the ground electrode are installed with a distance a4 and form a slit A4.

  The ground electrode 40 that forms the second plasma discharge space is covered with a dielectric 41, and a base material (film) F is placed thereon. The electrodes 43A and 43B forming the second plasma discharge space are covered with dielectrics 46A and 46B, respectively. The electrode and the ground electrode 40 are installed at a distance b4 to form a slit B4.

  The flow path for supplying the second discharge gas and the second cracked gas to the second discharge space has a slit C4 and a distance d4 between the insulator 44A and the electrode 43A installed in parallel with a distance c4. The gas is supplied to the slit D4 between the insulator 44B and the electrode 43B, which are installed in parallel with a distance, through the gas ejection portions 48C and 48D. There is no discharge between the slits C4 and D4, and there is no plasma discharge space.

  40, 42A, 42B, 43A, and 43B have hollow portions so that the liquid for adjusting the temperature can circulate, and the electrode temperature can be set independently.

  Since the application electrode 42A that forms the first plasma discharge space and the application electrodes 43A and 43B that form the second plasma discharge space are all connected to the same power source RF, the first plasma discharge space and the second plasma discharge space In order to control the electric field applied to the plasma discharge space, the distance a4, b4 between the ground electrode and the application electrode constituting the plasma discharge space is controlled. In order to satisfy the above condition of E2 ≧ E1, a4 ≧ b4 may be satisfied.

  The source gas is supplied from the outside of the electrode support member, and is supplied to the first plasma discharge space A4 through the gas ejection part 48A. The source gas decomposed in the first plasma discharge space A4 is continuously supplied to the second plasma discharge space B4. At that time, the raw material gas is introduced from the base material F from the position above e4, and further, the second discharge gas and the second decomposition gas are supplied from the base material from the position above b4 through the slits C4 and D4. Since b4> e4, a concentration gradient in which the source gas is unevenly distributed in the vicinity of the substrate can be formed in the second plasma discharge space, and a larger amount of decomposed material gas is deposited on the substrate F. The film forming yield can be increased.

  FIG. 5 is a configuration diagram of an example of a plasma CVD apparatus in which a plurality of electrode sets shown in FIG. 3 are prepared and the electrode supporting the base film is a roll electrode.

  In the plasma CVD apparatus of FIG. 5, the film-like substrate F is conveyed while being wound around a roll electrode 50 that rotates in the conveying direction (clockwise in the figure). A plurality of upper electrode sets 51A and 51B installed facing the periphery of the roll electrode 50 represent electrodes (a set of bar electrode structures indicated by 32A to 35A and 32B to 35B) from the top in FIG. ing. Reference numeral 52 denotes a support member for a gas supply unit that supplies a source gas between the electrodes 51A and 51B and the slit.

  The roll electrode 50 is a ground electrode, and the electrodes 51A and 51B are actually a structure in which the application electrode and the ground electrode are appropriately combined as described above. However, in FIG. Only the wiring of the application electrode is shown. A first plasma discharge space is formed between the electrodes 51A and 51B, and a second plasma discharge space is formed between the electrodes 51A and 51B and the roll electrode 50. The substrate F wound around the roll electrode 50 by the guide rollers 53 and 54 is sequentially reactive while being exposed only to the second plasma discharge space formed between the upper electrodes 51A and 51B and the roll electrode 50. A gas-derived metal oxide thin film is formed.

  Although not shown, when the electrodes as shown in FIG. 4 are used, the electrodes 51A and 51B facing the roll electrodes represent the set of 42A to 46A and 43B to 46B in FIG.

  In the present invention, since the film can be formed by the discharge treatment under a pressure close to atmospheric pressure instead of a vacuum system, such a continuous process becomes possible and high productivity can be raised.

  Next, conditions for forming a film under an atmospheric pressure or a pressure near atmospheric pressure using the electrode having such a shape will be described.

  The distances a3, b3, a4, and b4 between the electrodes forming the discharge space are preferably 0.3 mm to 20 mm, and particularly preferably 1 mm ± 0.5 mm. The distance between the electrodes is determined so that the gas phase space becomes the above-mentioned distance in consideration of the thickness of the dielectric around the electrodes and the thickness of the substrate to be formed.

  In order to adjust the electric field strength in the first plasma discharge space and the second plasma discharge space to E2 ≧ E1, b3 ≧ a3 or b4 ≧ a4 may be set. However, it is necessary that 20 mm ≧ a3, b3, a4, b4 ≧ 0.3 mm. Outside this range, plasma discharge may not occur.

  As the power source of the plasma film forming apparatus used for forming the film of the present invention, such as the power source RF in FIGS. 3 and 4, a power source capable of supplying a certain amount of power with a high frequency voltage is preferable. Specifically, a high-frequency power source of 1 kHz to 2500 MHz is preferable, and a voltage of any frequency between 1 kHz and 1 MHz and a voltage of any frequency between 1 MHz to 2500 MHz are applied in a superimposed manner. It is more preferable. This is because the frequency required for excitation of various gases existing in the discharge space may be different, so that the decomposition of the source gas is faster and the film forming speed is faster when a plurality of frequencies are applied. .

The lower limit value of the power supplied between the electrodes is preferably 0.1 W / cm ² or more and 50 W / cm ² or less, and more preferably 0.5 W / cm ² or more. In addition, when a voltage having a frequency of 1 kHz to 1 MHz and a voltage having a frequency of 1 MHz to 2500 MHz are superimposed, the voltage of 1 MHz to 2500 MHz is preferably smaller than the voltage having a frequency of 1 kHz to 1 MHz. The voltage is preferably 20% to 80%. The voltage application area (cm ² ) in the electrode is the area where discharge occurs.

The high-frequency voltage applied between the electrodes may be an intermittent pulse wave or a continuous sine wave, but a sine wave is preferable because the film forming speed increases.

  Such a power source is not particularly limited, but is a Shinko electric high frequency power source (3 kHz), a Shinko electric high frequency power source (5 kHz), a Shinko electric high frequency power source (15 kHz), a Shinko electric high frequency power source (50 kHz), HEIDEN High frequency power source manufactured by R & D Laboratories (continuous mode, 100 kHz), high frequency power source manufactured by Pearl Industry (200 kHz), high frequency power source manufactured by Pearl Industry (800 kHz), high frequency power source manufactured by Pearl Industrial (2 MHz), high frequency power source manufactured by JEOL (13.56 MHz) A high frequency power source (27 MHz) manufactured by Pearl Industry, a high frequency power source (150 MHz) manufactured by Pearl Industry, or the like can be used. Alternatively, a power source that oscillates at 433 MHz, 800 MHz, 1.3 GHz, 1.5 GHz, 1.9 GHz, 2.45 GHz, 5.2 GHz, 10 GHz, 28 GHz, or 110 GHz may be used. However, since it is difficult to efficiently and uniformly introduce it into the plasma space at a current of 2500 MHz or higher, it is preferably 2500 MHz or lower.

  Next, the metallic base material and dielectrics 31, 35A, 35B, 41, 44A, 44B, 46A, 46B forming the support members 30, 40 and the electrodes 32A, 32B, 33A, 33B, 42A, 42B, 45A, 45B. Will be described.

  The combination of the metallic base material and the dielectric is preferably one that matches the characteristics between the two. As one of the characteristics, the difference in linear thermal expansion coefficient between the metallic base material and the dielectric is 10.0 ppm / It is a combination which becomes below ℃. Preferably it is 8.0 ppm / degrees C or less, More preferably, it is 5.0 ppm / degrees C or less, More preferably, it is 2.0 ppm / degrees C or less. The linear thermal expansion coefficient is a well-known physical property value of a material.

  For example, (1) The metallic base material is pure titanium or a titanium alloy, and the dielectric is ceramic sprayed. (2) Metal base material is pure titanium or titanium alloy, dielectric is glass lining, (3) Metal base material is stainless steel, dielectric is ceramic sprayed coating, (4) Metal base material Stainless steel, dielectric is glass lining, (5) metal base is ceramic and iron composite, dielectric is ceramic spray coating, (6) metal base is ceramic and iron composite, dielectric The body is glass lining, (7) the metallic base material is a composite material of ceramics and aluminum, the dielectric is a ceramic sprayed coating, and (8) the metallic base material is ceramics and aluminum. In the composite material, glass-lined dielectric, and the like. From the viewpoint of the difference in linear thermal expansion coefficient, the above (1) or (2) and (5) to (8) are preferable, and (1) is particularly preferable.

  As the metallic base material, titanium or a titanium alloy is particularly useful. By using a metal base material of titanium or titanium alloy and a dielectric material corresponding to the above combination, there is no deterioration of the electrode in use, especially cracking, peeling, dropping off, etc., and long-term use under harsh conditions It becomes possible to endure.

  The metallic base material of the electrode useful in the present invention is a titanium alloy or titanium metal containing 70% by mass or more of titanium. In the present invention, if the titanium content in the titanium alloy or titanium metal is 70% by mass or more, it can be used without any problem, but preferably contains 80% by mass or more of titanium. As the titanium alloy or titanium metal useful in the present invention, those generally used as industrial pure titanium, corrosion resistant titanium, high strength titanium and the like can be used. Examples of the pure titanium for industrial use include TIA, TIB, TIC, TID, etc., all of which contain very few iron atoms, carbon atoms, nitrogen atoms, oxygen atoms, hydrogen atoms, etc. Content has 99 mass% or more. As the corrosion-resistant titanium alloy, T15PB can be preferably used, and it contains lead in addition to the above-mentioned contained atoms, and the titanium content is 98% by mass or more. Further, as the titanium alloy, in addition to the above-mentioned atoms excluding lead, for example, T64, T325, T525, TA3, etc. containing aluminum and containing vanadium or tin can be preferably used. As titanium content, 85 mass% or more is contained. These titanium alloys or titanium metals have a thermal expansion coefficient that is about 1/2 smaller than that of stainless steel, such as AISI 316, and are well combined with a dielectric applied on the titanium alloy or titanium metal as a metallic base material. Can withstand use at high temperature for a long time.

  On the other hand, as a required characteristic of the dielectric, specifically, an inorganic compound having a relative dielectric constant of 6 to 45 is preferable, and examples of such a dielectric include alumina and silicon nitride. Examples thereof include glass lining materials such as ceramics, silicate glass, and borate glass. Among these, ceramic sprayed ones and those provided by glass lining are preferable. In particular, a dielectric provided by spraying alumina is preferable.

  Alternatively, as one of specifications that can withstand high power, the porosity of the dielectric is 10% by volume or less, preferably 8% by volume or less, preferably more than 0% by volume and 5% by volume or less. Another preferable specification that can withstand high power is that the thickness of the dielectric is 0.5 to 2 mm. The film thickness variation is desirably 5% or less, preferably 3% or less, and more preferably 1% or less.

  Further, it is preferable that the corners of the electrodes are formed in an arc shape, and the corners of the dielectric covering the electrodes are accordingly formed in an arc shape. The corners in a state where the electrodes are covered with a dielectric are preferably arcs having a radius of 3 mm or more. An arc having a radius of 3 mm or less is not preferable because the applied electric field concentrates on the corners and causes arc discharge.

  Next, a preferable raw material gas for obtaining a metal oxide thin film will be described.

  The raw material for the metal oxide thin film may be in a gas, liquid, or solid state at normal temperature and pressure. In the case of gas, it can be introduced into the discharge space as it is, but in the case of liquid or solid, it is used after being vaporized by means such as heating, bubbling, decompression, ultrasonic irradiation, vaporizer or the like. Moreover, you may dilute and use with a solvent and organic solvents, such as methanol, ethanol, n-hexane, and these mixed solvents can be used for a solvent. Since these diluted solvents are decomposed into molecular and atomic forms during the plasma discharge treatment, the influence can be almost ignored.

  However, it is preferably an organometallic compound having a vapor pressure in the temperature range of 0 ° C. to 250 ° C. under atmospheric pressure, and more preferably an organometallic compound exhibiting a liquid state in the temperature range of 0 to 250 ° C. This is because the plasma deposition chamber is at a pressure close to atmospheric pressure, and it is difficult to send gas into the plasma deposition chamber unless it can be vaporized under atmospheric pressure. This is because the amount of the raw material compound that is fed into the plasma film forming chamber can be accurately controlled. In particular, when the raw material compound is a liquid, a vaporizer can be used. The vaporizer can directly vaporize from the liquid, and the amount of vaporization can be managed with an accuracy of ± 1%. In addition, when the heat resistance of the plastic film which forms a gas barrier layer is 270 degrees C or less, it is preferable that it is a compound which has a vapor pressure from the plastic film heat resistant temperature to the temperature of 20 degrees C or less.

Examples of such organometallic compounds include silicon-containing compounds such as silane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, and tetra-t-butoxysilane. , Dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, phenyltriethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, hexamethyl Disiloxane,
Bis (dimethylamino) dimethylsilane, bis (dimethylamino) methylvinylsilane, bis (ethylamino) dimethylsilane, N, O-bis (trimethylsilyl) acetamide, bis (trimethylsilyl) carbodiimide, diethylaminotrimethylsilane, dimethylaminodimethylsilane, hexa Methyldisilazane, hexamethylcyclotrisilazane, heptamethyldisilazane, nonamethyltrisilazane, octamethylcyclotetrasilazane, tetrakisdimethylaminosilane, tetraisocyanatosilane, tetramethyldisilazane, tris (dimethylamino) silane, triethoxyfluoro Silane,
Allyldimethylsilane, allyltrimethylsilane, benzyltrimethylsilane, bis (trimethylsilyl) acetylene, 1,4-bistrimethylsilyl-1,3-butadiyne, di-t-butylsilane, 1,3-disilabutane, bis (trimethylsilyl) methane, cyclo Pentadienyltrimethylsilane, phenyldimethylsilane, phenyltrimethylsilane, propargyltrimethylsilane, tetramethylsilane, trimethylsilylacetylene, 1- (trimethylsilyl) -1-propyne, tris (trimethylsilyl) methane, tris (trimethylsilyl) silane, vinyltrimethylsilane , Hexamethyldisilane, and the like.

  Examples of the titanium-containing compound include titanium methoxide, titanium ethoxide, titanium isopropoxide, titanium n-butoxide, titanium diisopropoxide (bis-2,4-pentanedionate), and titanium diisopropoxy. (Bis-2,4-ethylacetoacetate), titanium di-n-butoxide (bis-2,4-pentanedionate), titanium acetylacetonate, butyl titanate dimer, and the like.

  The compounds containing zirconium include zirconium n-propoxide, zirconium n-butoxide, zirconium t-butoxide, zirconium tri-n-butoxide acetylacetonate, zirconium di-n-butoxide bisacetylacetonate, zirconium acetylacetonate. , Zirconium acetate, zirconium hexafluoropentanedionate and the like.

  Examples of the compound containing aluminum include aluminum ethoxide, aluminum isopropoxide, aluminum n-butoxide, aluminum s-butoxide, aluminum t-butoxide, and aluminum acetylacetonate.

  Examples of the boron-containing compound include diborane, tetraborane, boron fluoride, boron chloride, boron bromide, borane-diethyl ether complex, borane-THF complex, borane-dimethyl sulfide complex, boron trifluoride diethyl ether complex, Examples thereof include triethylborane, trimethoxyborane, triethoxyborane, tri (isopropoxy) borane, borazole, trimethylborazole, triethylborazole, triisopropylborazole, and the like.

  Compounds containing tin include tetraethyltin, tetramethyltin, di-n-butyltin diacetate, tetrabutyltin, tetraoctyltin, tetraethoxytin, methyltriethoxytin, diethyldiethoxytin, triisopropylethoxytin, Diethyltin, dimethyltin, diisopropyltin, dibutyltin, diethoxytin, dimethoxytin, diisopropoxytin, dibutoxytin, tin dibutyrate, tin diacetoacetonate, ethyltin acetoacetonate, ethoxytin acetoacetonate, dimethyltin di Examples of tin halides such as acetoacetonate and tin hydrogen compounds include tin dichloride and tin tetrachloride.

  Examples of organic compounds composed of other metals include antimony ethoxide, arsenic triethoxide, barium 2,2,6,6-tetramethylheptanedionate, beryllium acetylacetonate, bismuth hexafluoropentanedionate, dimethylcadmium, Calcium 2,2,6,6-tetramethylheptanedionate, chromium trifluoropentanedionate, cobalt acetylacetonate, copper ethylacetoacetate, copper hexafluoropentanedionate, magnesium acetate, magnesium trifluoroacetate, magnesium trifluoro Pentanedionate, magnesium hexafluoropentanedionate, magnesium hexafluoropentanedionate-dimethyl ether complex, gallium ethoxide, tetraether Xigermane, tetramethoxygermane, hafnium t-butoxide, hafnium ethoxide, indium acetylacetonate, indium 2,6-dimethylaminoheptanedionate, ferrocene, lanthanum isopropoxide, lead acetate, tetraethyllead, neodymium acetylacetonate, platinum Hexafluoropentanedionate, trimethylcyclopentadienylplatinum, rhodium dicarbonylacetylacetonate, strontium 2,2,6,6-tetramethylheptanedionate, tantalum methoxide, tantalum trifluoroethoxide, tellurium ethoxide, tungsten Examples include ethoxide, vanadium triisopropoxide oxide, zinc acetylacetonate, and diethyl zinc.

  Of these organometallic compounds, organosilicon compounds are preferred. This is because the organosilicon compound has high volatility, is cheaper than other metal compounds, and the silicon oxide thin film obtained from the organosilicon compound has high gas barrier properties and transparency.

  These raw material gases are diluted with the discharge gas to maintain the plasma discharge and are introduced into the plasma discharge space. As such a discharge gas, nitrogen gas and / or an 18th group atom of the periodic table, specifically helium, neon, argon, krypton, xenon, radon, etc., particularly helium and argon are preferably used. Furthermore, a cracked gas such as hydrogen gas may be mixed in the mixed gas as described above in order to adjust the carbon and hydrogen content in the film.

  As described above, the film is formed by mixing the discharge gas, the raw material gas, and the decomposition gas and supplying the mixed gas to the plasma discharge space. Although the ratio of the discharge gas and the raw material gas varies depending on the properties of the film to be obtained, the reactive gas is supplied with the ratio of the discharge gas being 90.0 to 99.9% with respect to the entire mixed gas.

  The resin base material for forming the metal oxide thin film of the present invention is not particularly limited as long as it is substantially transparent. Specifically, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyethylene, polypropylene, cellophane, and cellulose. Cellulose esters such as diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, Polycarbonate, norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone, polysulfones, polyether Ruketon'imido, polyamide, fluorine resin, nylon, polymethyl methacrylate, acrylic or polyarylates, or can be exemplified organic-inorganic hybrid resins and the like of these resins and silica.

  However, the metal oxide thin film formed by atmospheric pressure plasma CVD method has a higher gas barrier property as the film forming temperature is higher, and various heating processes such as formation of a transparent conductive film as a transparent substrate (support) for display. Therefore, it is preferable that the resin forming the metal oxide thin film has high heat resistance.

  As the heat resistance, the glass transition temperature is preferably 180 ° C. or higher. Resin base materials that satisfy these conditions include some polycarbonates, some cycloolefin polymers, polyethersulfone, polyetheretherketone, polyimide, fluororesin, diacetylcellulose, triacetylcellulose, and these resins. Examples thereof include organic-inorganic hybrid resins of silica.

  In addition, as a method of measuring the glass transition temperature of the resin base material, it can be measured by DSC (differential scanning calorimetry), TMA (thermal stress strain measurement), DMA (dynamic viscoelasticity measurement) and the like.

  Of these, diacetylcellulose, triacetylcellulose, and organic-inorganic hybrid resins of silica and silica having high transparency, low birefringence, and positive birefringence wavelength dispersion characteristics are preferable.

  An organic-inorganic hybrid resin (or called an organic-inorganic polymer composite or the like) is a material in which an organic polymer and an inorganic compound are combined to give both characteristics. By using a method of synthesizing an inorganic substance to be mixed with an organic polymer from a liquid state such as a metal alkoxide (referred to as a sol-gel method), the inorganic fine particles to be generated are nanoscale below the wavelength of visible light (up to about 750 nm). Thus, it is possible to disperse in an organic substance, and a material which is optically transparent and has high heat resistance can be obtained.

  In the present invention, since the resin substrate is directly exposed to a plasma atmosphere, it may have an undercoat layer on one side or both sides as a plasma etching layer or a hard coat layer. Specific examples of the undercoat layer include an organic layer formed by applying a polymer or the like. The organic layer includes, for example, a film obtained by subjecting an organic material film having a polymerizable group to post-treatment by means such as ultraviolet irradiation or heating.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1 (Measurement of film forming yield)
<Film formation of diacetylcellulose-silica hybrid film>
Into the mixing tank, 25 parts by mass of tetramethoxysilane, 15 parts by mass of ethanol, 15 parts by mass of methylene chloride, and 12 parts by mass of 0.5% nitric acid aqueous solution were added and stirred while cooling to 0 ° C. to carry out a sol-gel reaction.

  Furthermore, 45 parts by mass of ethanol, 660 parts by mass of methylene chloride, and 100 parts by mass of diacetylcellulose were added to a mixing tank, and dissolved by stirring at 80 ° C. while stirring.

  The obtained dope (dissolved solution) was cast using a band casting machine, and when the residual solvent amount reached 50%, it was peeled off from the band, immediately transported to a tenter, and then 30% in the orthogonal direction. The film was stretched 30% in the flow direction. Thereafter, it was dried at 120 ° C. for 5 minutes and then at 220 ° C. for 5 minutes to obtain a diacetylcellulose-silica hybrid film. The film thickness was adjusted so as to be finally 80 μm.

  The refractive index of the obtained diacetylcellulose-silica hybrid film was 1.48, and the glass transition temperature was 225 ° C. as measured by TMA (thermal stress strain measuring device). The average linear expansion coefficient from 30 ° C. to 180 ° C. was 27 ppm / ° C.

<Preparation of clear hard coat layer>
On the obtained diacetylcellulose-silica hybrid film, the following hard coat layer coating composition was coated with an extrusion coater so as to have a film thickness of 3 μm, and then dried in a drying section set at 80 ° C. for 1 minute. It was formed by irradiating with ultraviolet rays at 120 mW / cm ² .

The clear hard coat layer had a refractive index of 1.54 and a coating film thickness of 5000 μm. The water vapor permeability of the diacetylcellulose-silica hybrid film provided with the clear hard coat layer was 840 g / m ² / d.

<Clear hard coat layer coating composition>
Dipentaerythritol hexaacrylate monomer 60 parts by weight Dipentaerythritol hexaacrylate dimer 20 parts by weight Dipentaerythritol hexaacrylate trimer or higher component 20 parts by weight Dimethoxybenzophenone 4 parts by weight Ethyl acetate 50 parts by weight Methyl ethyl ketone 50 parts by mass Isopropyl alcohol 50 parts by mass The plasma discharge electrode shown in FIG. 1, FIG. 3 or FIG. 4 is applied to the plasma CVD shown in FIG. 5 on the diacetylcellulose-silica hybrid film coated with the above clear hard coat layer. A plasma discharge space is formed under atmospheric pressure using a high frequency power source JRF10000 manufactured by JEOL Ltd. as a 13.56 MHz power source and a high frequency power source PHF-2K manufactured by HEIDEN Laboratory as a 100 kHz power source. ,following It was formed of silicon oxide thin film using the gas A-E.

<Silicon oxide source gas A>
Discharge gas: Argon 99.3% by volume
Cracked gas: 0.5% by volume of hydrogen
Source gas: Tetraethoxysilane (TEOS) 0.2% by volume
Vaporization temperature: 30 ° C
<Silicon oxide source gas B>
Discharge gas: Nitrogen 99.3% by volume
Cracked gas: 0.5% by volume of hydrogen
Source gas: TEOS 0.2% by volume
Vaporization temperature: 30 ° C
<Second discharge gas C>
Discharge gas: Argon 100% by volume
<Second discharge gas D>
Discharge gas: Argon 99.5% by volume
Cracked gas: Oxygen 0.5% by volume
<Second discharge gas E>
Discharge gas: Nitrogen 99.5% by volume
Cracked gas: Oxygen 0.5% by volume
<Composition analysis>
The mixing ratio of carbon and nitrogen was measured using an X-ray photoelectron spectroscopic analyzer (ESCA) manufactured by VG Scientific.

<Water vapor permeability test>
Using a water vapor transmission rate measuring device PERMATRAN-W1A manufactured by Modern Control, water vapor transmission rate (WVTR) was measured under conditions of 37 ° C. and 90% RH.

<Oxygen permeability test>
The oxygen transmission rate (OTR) was measured under conditions of 23 ° C. and 0% RH using an oxygen transmission rate measuring device OX-TRAN100 manufactured by Modern Control.

<Film formation yield measurement>
The density of the silicon oxide was set to 2.15, and the mass of the silicon oxide film formed with a film forming area × film thickness × 2.15 g / cm ³ was calculated. The film forming area was film width × film roll length, and the film thickness was measured using FE3000 manufactured by Otsuka Electronics. In this example, the electrode width was set to 13.5 cm and the length of the film roll was set to 7.5 m. Moreover, the mass W of TEOS consumed at the time of film forming was measured, and the film forming yield was calculated. Since 28.8 parts by mass of silicon oxide is produced from 100 parts by mass of TEOS, the yield Y (%) is obtained from the film thickness d (cm) and TEOS consumption W (g) by the following formula.

(D × 13.5 × 750 × 2.15) / (W × 0.288) × 100 = Y
In addition, in order to make it easy to compare the results of measurement of water vapor transmission rate and oxygen transmission rate, the film forming speed is calculated according to each condition, and the silicon oxide thin film of about 110 to 120 nm is obtained by changing the number of passes. Filmed.

<Film Formation of Gas Barrier Film 1 of Comparative Example>
A silicon oxide source gas A was used to form a silicon oxide film with parallel plate electrodes as shown in FIG. The inter-electrode distance a1 was 1.0 mm, b1 was 1.0 mm, and the temperatures of the electrodes 12A, 12B, and 10 were set to 90 ° C. The discharge area is 30 mm × 2 electrode width × 150 mm electrode length = 90 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop shape and conveyed at 7.5 m / min, and 30 passes of film formation were performed. . The silicon oxide source gas A was supplied at 45 slm. Vpp (peak-to-peak) when a high frequency electric field was applied was 5 kV.

  Since the film thickness after 30 passes was 115 nm and the TEOS consumption was 4.57 g, the yield was 18.7%.

Further, this gas barrier film had a water vapor transmission rate of 1.55 g / m ² / d and an oxygen transmission rate of 1.95 cc / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Formation of Gas Barrier Film 2 of Example>
A silicon oxide source gas A was used to form a silicon oxide film with electrodes as shown in FIG. The interelectrode distance a3 was 1.0 mm, b3 was 1.0 mm, and the temperatures of the electrodes 32A, 32B, 33A, 33B, 30 were set to 90 ° C. The discharge area of the first plasma discharge space is 30 mm electrode width × 150 mm electrode length = 45 cm ² , and the second plasma discharge space is 30 mm electrode width × 2 electrodes × 150 mm electrode length = 90 cm ^2. The discharge area is 135 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop and conveyed at 7.5 m / min, and 20 passes of film formation were performed. . The silicon oxide source gas A was supplied at 45 slm. Vpp at the time of electric field application was 5 kV.

  Since the film thickness after 20 passes was 122 nm and the TEOS consumption was 3.02 g, the yield Y was 30.2%.

The gas barrier film had a water vapor transmission rate of 0.73 g / m ² / d and an oxygen transmission rate of 0.95 cc / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Formation of Gas Barrier Film 3 of Example>
A silicon oxide source gas A was used to form a silicon oxide film with the electrodes shown in FIG. The inter-electrode distance a3 was 1.0 mm, b3 was 0.8 mm, and the temperature of the electrodes 32A, 32B, 33A, 33B, 30 was set to 90 ° C. The discharge area of the first plasma discharge space is electrode width 30 mm × electrode length 150 mm = 45 cm ² , and the second plasma discharge space is electrode width 30 mm × 2 pieces × electrode length 150 mm = 90 cm ² , The discharge area is 135 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop and conveyed at 7.5 m / min, and 18 pass film formation was performed. . The silicon oxide source gas A was supplied at 45 slm. Vpp at the time of electric field application was 5 kV.

  Since the film thickness after 18 passes was 118 nm and the TEOS consumption was 2.74 g, the yield Y was 32.5%.

The gas barrier film had a water vapor transmission rate of 0.33 g / m ² / d and an oxygen transmission rate of 0.45 ml / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Formation of Gas Barrier Film 4 of Comparative Example>
A silicon oxide source gas A was used to form a silicon oxide film with the electrodes shown in FIG. The interelectrode distance a3 was 1.0 mm, b3 was 1.5 mm, and the temperatures of the electrodes 32A, 32B, 33A, 33B, 30 were set to 90 ° C. The discharge area of the first plasma discharge space is electrode width 30 mm × electrode length 150 mm = 45 cm ² , and the second plasma discharge space is electrode width 30 mm × 2 pieces × electrode length 150 mm = 90 cm ² , The discharge area is 135 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop and conveyed at 7.5 m / min, and 20 passes of film formation were performed. . The silicon oxide source gas A was supplied at 45 slm. Vpp at the time of electric field application was 5 kV.

  Since the film thickness after 36 passes was 117 nm and the TEOS consumption was 5.47 g, the yield Y was 16.2%.

The gas barrier film had a water vapor transmission rate of 1.03 g / m ² / d and an oxygen transmission rate of 1.24 ml / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Formation of Gas Barrier Film 5 of Example>
A silicon oxide source gas A was used to form a silicon oxide film with electrodes as shown in FIG. The distance a3 between the electrodes was 1.0 mm, b3 was 1.0 mm, the temperature of the electrodes 32A and 32B was set to 90 ° C., and the temperature of the 33A, 33B and 30 was set to 180 ° C. The discharge area of the first plasma discharge space is electrode width 30 mm × electrode length 150 mm = 45 cm ² , and the second plasma discharge space is electrode width 30 mm × 2 pieces × electrode length 150 mm = 90 cm ² , The discharge area is 135 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop and conveyed at 7.5 m / min, and 18 pass film formation was performed. . The silicon oxide source gas A was supplied at 45 slm. Vpp at the time of electric field application was 5 kV.

  Since the film thickness after 18 passes was 112 nm and the TEOS consumption was 2.75 g, the yield Y was 30.8%.

Further, this gas barrier film had a water vapor transmission rate of 0.081 g / m ² / d and an oxygen transmission rate of 0.11 ml / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Formation of Gas Barrier Film 6 of Example>
Using silicon oxide source gas A, a silicon oxide film was formed with electrodes as shown in FIG. The inter-electrode distance a3 was 1.0 mm, b3 was 1.0 mm, and the temperatures of the electrodes 42A, 42B, 43A, 43B, and 30 were set to 90 ° C. The discharge area of the first plasma discharge space is electrode width 30 mm × electrode length 150 mm = 45 cm ² , and the second plasma discharge space is electrode width 30 mm × 2 pieces × electrode length 150 mm = 90 cm ² , The discharge area is 135 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop and conveyed at 7.5 m / min, and a 16-pass film was formed. . The silicon oxide source gas A was supplied at 45 slm. The second discharge gas C was introduced at 45 slm into the slits C4A and C4B. Vpp at the time of electric field application was 5 kV.

  Since the film thickness after 16 passes was 115 nm and the TEOS consumption was 2.44 g, the yield Y was 35.6%.

The gas barrier film had a water vapor transmission rate of 0.51 g / m ² / d and an oxygen transmission rate of 0.66 ml / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Formation of Gas Barrier Film 7 of Example>
Using silicon oxide source gas A, a silicon oxide film was formed with electrodes as shown in FIG. The inter-electrode distance a3 was 1.0 mm, b3 was 1.0 mm, and the temperatures of the electrodes 42A, 42B, 43A, 43B, and 40 were set to 180 ° C. The discharge area of the first plasma discharge space is electrode width 30 mm × electrode length 150 mm = 45 cm ² , and the second plasma discharge space is electrode width 30 mm × 2 pieces × electrode length 150 mm = 90 cm ² , The discharge area is 135 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop and conveyed at 7.5 m / min, and a 15-pass film was formed. . The silicon oxide source gas A was supplied at 45 slm. Further, the second cracked gas D was introduced at 45 slm from the slits C4A and C4B. Vpp at the time of electric field application was 5 kV.

  Since the film thickness after 15 passes was 113 nm and the TEOS consumption was 2.29 g, the yield Y was 37.3%.

The gas barrier film had a water vapor transmission rate of 0.14 g / m ² / d and an oxygen transmission rate of 0.20 ml / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Film Formation of Gas Barrier Film 8 in Examples>
Using silicon oxide source gas A, a silicon oxide film was formed with electrodes as shown in FIG. The inter-electrode distance a3 was 1.0 mm, b3 was 1.0 mm, the temperatures of the electrodes 42A and 42B were set to 90 ° C., and the temperatures of the 43A, 43B and 40 were set to 180 ° C. The discharge area of the first plasma discharge space is electrode width 30 mm × electrode length 150 mm = 45 cm ² , and the second plasma discharge space is electrode width 30 mm × 2 pieces × electrode length 150 mm = 90 cm ² , The discharge area is 135 cm ² . A high frequency electric field of 13.56 MHz was applied to such an electrode at 10 W / cm ² , a 7.5 m long film was connected in a loop and conveyed at 7.5 m / min, and a 15-pass film was formed. . The silicon oxide source gas A was supplied at 45 slm. Moreover, the discharge gas D was introduced into both slits C4 at 45 slm. Vpp at the time of electric field application was 5 kV.

  Since the film thickness after 15 passes was 111 nm and the TEOS consumption was 2.28 g, the yield Y was 36.8%.

Further, this gas barrier film had a water vapor transmission rate of 0.07 g / m ² / d and an oxygen transmission rate of 0.09 ml / m ² / d. Further, when the carbon content of the silicon oxide film was measured by XPS, it was 1.0% or less.

<Film Formation of Gas Barrier Film 9 in Examples>
Using silicon oxide source gas B, a silicon oxide film was formed with electrodes as shown in FIG. The inter-electrode distance a3 was 0.7 mm, b3 was 0.5 mm, the temperatures of the electrodes 42A and 42B were set to 90 ° C., and the temperatures of the 43A, 43B and 40 were set to 180 ° C.

The discharge area of the first plasma discharge space is electrode width 30 mm × electrode length 150 mm = 45 cm ² , and the second plasma discharge space is electrode width 30 mm × 2 pieces × electrode length 150 mm = 90 cm ² , The discharge area is 135 cm ² . A high frequency electric field of 100 kHz was applied to such an electrode at 14 k / cm ² at 0.2 kV and a high frequency electric field of 13.56 MHz at 10 W / cm ² (Vpp = 5 kV), and a 7.5 m long film was looped. The films were connected and transported at 7.5 m / min to form 11 passes. The silicon oxide source gas 1 was supplied at 45 slm. Further, the discharge gas E was introduced into both slits C4 at 45 slm.

  Since the film thickness after 11 passes was 111 nm and the TEOS consumption was 1.67 g, the yield Y was 50.2%.

Further, this gas barrier film had a water vapor transmission rate (WVTR) of 0.12 g / m ² / d and an oxygen transmission rate (OTR) of 0.25 cc / m ² / d. Further, when the carbon and nitrogen contents of the silicon oxide film were measured by XPS, they were each 1.0% or less.

  Table 1 shows the film formation yield, the number of passes, WVTR, and OTR of the gas barrier films 1 to 9 of Examples or Comparative Examples.

Electrode shape: Displayed with figure numbers 1 to 4 E1: Electric field strength applied to the first plasma discharge space E2: Electric field strength applied to the second plasma discharge space T1: Forming the first plasma discharge space Temperature of the pair of electrodes T2: Temperature of the pair of electrodes forming the second plasma discharge space From Table 1, it can be seen that the film formation yield is high in the plasma CVD method according to the electrode configuration of the present invention. As a result of the high film formation yield, the number of passes required for film formation with a constant film thickness can be reduced, and high productivity can be achieved. In particular, in the gas barrier film 9 in which two high-frequency electric fields are superimposed, the film formation yield exceeds 50%, the number of passes can be suppressed to about 1/3 that of the gas barrier film 1, and high productivity can be obtained.

  Further, introducing the second decomposition gas into the second plasma discharge space and increasing the temperature of the electrodes constituting the second plasma discharge space not only improves the film forming yield but also improves the gas barrier property. It can be seen that the effect is great.

FIG. 2 is a configuration diagram of the most common electrode in the plasma CVD method. The block diagram of a plasma jet type electrode. The block diagram of the electrode for plasma CVD which has the 1st plasma discharge space and the 2nd plasma discharge space. The electrode block diagram which can supply with the high source gas density | concentration of the base-material vicinity in 2nd plasma discharge space. The block diagram of an example of the plasma CVD apparatus which prepared multiple sets of electrodes and used the electrode which supports a base film as a roll-shaped electrode.

Explanation of symbols

10, 20, 23, 30, 32B, 40, 42B, 50 Ground electrode 12A, 12B, 22, 32A, 33A, 33B, 35A, 35B, 42A, 43A, 43B, 51A, 51B Applied electrode 34A, 34B Insulator 11 , 21, 31, 41 Dielectrics a1, b1, a2, b2, a3, b3, a4, b4, c4, d4, e4 Distance between slits F Substrate (film)
RF power supply

Claims (16)

An atmospheric pressure plasma CVD in which a source gas containing a thin film source is introduced into the second plasma discharge space after passing through the first plasma discharge space and forms a thin film on the substrate in the second plasma discharge space A method of forming a thin film by a method,
A method of forming a thin film, wherein the electric field intensity E1 applied to the first plasma discharge space and the electric field intensity E2 applied to the second plasma discharge space satisfy the following formula (1):
E2 ≧ E1 (1) The temperature T1 of the pair of electrodes forming the first plasma discharge space and the temperature T2 of the pair of electrodes forming the second plasma discharge space satisfy the following formula (2): The method for forming a thin film according to claim 1.
T2 ≧ T1 (2) A first inert gas, a raw material gas, and a first decomposition gas are introduced into the first plasma discharge space, and a gas passing through the first plasma discharge space, a first gas, and the like are introduced into the second plasma discharge space. 2. The method for forming a thin film according to claim 1, wherein two inert gases and a second cracked gas are introduced. A gas passing through the first plasma discharge space is introduced onto the substrate in the second plasma discharge space, and a second inert gas and a second gas are introduced above the gas passing through the first plasma discharge space. The method for forming a thin film according to claim 1, wherein the decomposition gas is introduced. 5. The method for forming a thin film according to claim 1, wherein the first cracked gas is a reducing gas and the second cracked gas is an oxidizing gas. 6. 6. The thin film forming method according to claim 1, wherein the first plasma discharge space and the second plasma discharge space are continuous. 7. The method for forming a thin film according to claim 1, wherein both the first plasma discharge space and the second plasma discharge space are under atmospheric pressure or a pressure in the vicinity of atmospheric pressure. The high-frequency voltage applied to the electrode is in the range of 1 kHz to 2500 MHz, and the supplied power is in the range of 1 to 50 W / cm ^2. Method for forming a thin film. 9. The high frequency voltage according to claim 1, wherein an alternating voltage having a frequency in a range of 1 kHz to 1 MHz is superimposed on an alternating voltage having a frequency of 1 MHz to 2500 MHz. Method for forming a thin film. The thin film formed by the formation method of the thin film of any one of Claims 1-9 is an inorganic oxide thin film, The thin film characterized by the above-mentioned. A thin film formed by the method for forming a thin film according to claim 1, wherein the thin film is a silicon oxide thin film. It is a thin film formed with the formation method of the thin film of any one of Claims 1-9, Comprising: The water-vapor-permeation rate of this thin film is 1.0 g / m < ² > / d or less, It is characterized by the above-mentioned. Thin film. A thin film was formed into a film by forming a thin film according to any one of claims 1 to 9, the oxygen permeability of the thin film is 1.0cc / m ² /d(1.0ml/m ² / d ) A thin film characterized by: A transparent plastic film, wherein the thin film formed by the method for forming a thin film according to any one of claims 1 to 9 is formed on a transparent plastic film substrate. The transparent plastic film according to claim 14, wherein the glass transition temperature of the transparent plastic film substrate is 180 ° C or higher. The transparent plastic film according to claim 14 or 15, wherein the transparent plastic film substrate is a plastic film mainly composed of cellulose ester.

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