JP2006002224A - Thin-film-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin-film forming method which forms a high functional thin-film with great productivity, and forms the thin film having a crystalline property and high quality even on a heat-sensitive substrate such as a plastic material. <P>SOLUTION: The thin-film-forming method for supplying a gas containing a discharge gas and a thin-film-forming gas into a discharge space under ambient pressure or under the vicinity of the pressure, activating the gas by applying a high-frequency electric field to the discharge space, and forming the thin film on the substrate by exposing the substrate to the activated gas comprises: separately supplying the gas containing the discharge gas and the gas containing the thin-film-forming gas to the discharge space; and controlling the temperature of a gas mixture containing the discharge gas and the thin-film-forming gas in the discharge space to a range between 300°C and 3,000°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel thin film forming method using atmospheric pressure plasma discharge treatment and a substrate having a thin film formed by the thin film forming method.

  Semiconductor devices and various devices for display, recording, and photoelectric conversion are provided with a high-functional thin film on a substrate, for example, electrode film, dielectric protective film, semiconductor film, transparent conductive film, antireflection Various materials such as a film, an optical interference film, a hard coat film, an undercoat film, and a barrier film are used.

  In the production of such a highly functional thin film, conventionally, a dry film forming method using a vacuum such as a sputtering method, a vacuum vapor deposition method, an ion plating method or the like has been used.

  Since such a film forming method requires vacuum equipment, the equipment cost is high. Furthermore, since continuous production was not possible and the film formation rate was low, there was a problem that productivity was low.

  As a method for overcoming the disadvantages of low productivity due to the use of these vacuum devices, Japanese Patent Application Laid-Open No. 61-238961, etc., generates a discharge plasma under atmospheric pressure, and obtains a high treatment effect by the discharge plasma. Plasma processing methods have been proposed. In the atmospheric pressure plasma treatment method, a film can be formed on the surface of a substrate with a uniform composition, physical properties, and distribution. Further, since the treatment can be performed under atmospheric pressure or near atmospheric pressure, vacuum equipment is not required, equipment cost can be suppressed, continuous production can be supported, and a film formation rate can be increased. Examples of applications in which a thin film is formed on a substrate by discharging at atmospheric pressure or under a pressure near atmospheric pressure to excite a reactive gas to form a thin film on a substrate are disclosed in JP-A-11-133205, JP-A-2000-185362, 11-61406, JP-A 2000-147209, 2000-121804, etc. (hereinafter also referred to as atmospheric pressure plasma method). In the atmospheric pressure plasma method disclosed in these publications, an electric field that is pulsed between opposing electrodes, has a frequency of 0.5 to 100 kHz, and an electric field strength of 1 to 100 V / cm is applied. A discharge plasma of a reactive gas is generated.

  In the atmospheric pressure plasma discharge treatment, a mixed gas of a rare gas and a thin film-forming gas is used. However, in JP-A-10-154598, a pulse electric field is used so that a discharge gas other than a rare gas is inexpensive. It is disclosed that the discharge can be achieved even using a gas such as nitrogen gas, which has a high discharge starting electric field strength and is difficult to obtain a stable discharge under a conventional high-frequency electric field.

  As a method of forming a thin film using these atmospheric pressure plasma discharge treatments, for example, in Japanese Patent Laid-Open No. 6-330326, a metal oxide film is formed by adding a small amount of metal alkoxide or the like during atmospheric pressure plasma discharge. A method has been proposed.

  However, the above metal alkoxides, for example, organosilicon compounds, organotitanium compounds, organotin compounds, organozinc compounds, organoindium compounds, organoaluminum compounds, organocopper compounds, organosilver compounds, etc. are liquids at room temperature, Since the vapor pressure is not high, after vaporization by heating, it is necessary to mix with a rare gas such as helium or argon and introduce it between the opposing discharge electrodes, but if the electrode surface temperature is lower than the mixed gas, Components such as metal alkoxide condense on the electrode surface, it is not always a constant gas mixture, it is difficult to achieve uniform film formation, and the condensed part reacts and solidifies, clogging the gas passage I have a problem. On the other hand, as an anti-condensation measure in the electrode, for example, if the electrode is heated too much, non-uniform discharge due to partial dielectric breakdown or the like is induced, and uniform film formation cannot be performed.

  In Patent Document 1, in order to achieve uniform film formation in thin film formation using a thin film forming gas such as these metal alkoxides, and in order to suppress the condensation of the raw material gas to the electrode or gas passage, A method of separately supplying the discharge gas and the reactive gas is adopted.

  Further, in Patent Document 2, electrode contamination and the like are suppressed by making the rare gas and the reactive gas laminar flow and preventing the discharge surface of the electrode from being in direct contact with the reactive gas.

In this way, even in thin film formation using a thin film forming gas such as a metal alkoxide, a uniform thin film can be obtained without causing contamination of electrodes and flow paths due to condensation or the like. In atmospheric pressure plasma discharge treatment, it is known that increasing the substrate temperature during film formation improves the film quality due to the diffusion effect on the substrate surface. It is also known that when the temperature is increased to the crystallization temperature, the thin film is crystallized, and characteristics that cannot be obtained with amorphous are obtained. For example, in an ITO thin film, transparency and electrical conductivity are improved by crystallization, and in a TiO ₂ thin film, a photocatalytic function is exhibited by crystal transition to an anatase structure.

  However, these temperatures are extremely high, and when the base material on which the thin film is formed is made of, for example, a resin material, the deformation due to the temperature of the resin occurs, so that it cannot be applied.

In the present invention, as described above, the inert gas (discharge gas) and the reactive gas (thin film forming gas) are separately supplied to the discharge space, and the respective temperatures are controlled without deforming the substrate. In addition, the present invention provides a method for securing a plasma temperature in the discharge space and obtaining a uniform thin film.
JP 2003-155571 A JP 2003-166063 A

  Accordingly, in view of the above problems, an object of the present invention is a thin film forming method for forming a highly functional thin film with high productivity. A very high quality thin film having crystallinity is a substrate that is weak against heat such as plastic. Another object is to provide a method that can also be formed.

  The above object of the present invention is achieved by the following means.

(Claim 1)
A gas containing a discharge gas and a thin film forming gas is supplied to the discharge space under atmospheric pressure or a pressure in the vicinity thereof, the gas is excited by applying a high-frequency electric field to the discharge space, and the gas that excites the substrate In the thin film forming method of forming a thin film on the substrate by exposing to the gas, the discharge gas and the gas containing the thin film forming gas are separately supplied to the discharge space, and in the discharge space The method of forming a thin film, wherein the temperature of the mixed gas containing the discharge gas and the thin film forming gas is 300 ° C. or higher and 3000 ° C. or lower.

(Claim 2)
2. The thin film forming method according to claim 1, wherein a temperature of a mixed gas containing the discharge gas and the thin film forming gas in the discharge space is 500 ° C. or higher and 1000 ° C. or lower.

(Claim 3)
3. The thin film forming method according to claim 1, wherein in the discharge space, the temperature of the electrode supporting the base material is within a range of ± 50 ° C. with respect to the glass transition temperature of the base material.

(Claim 4)
The method of forming a thin film according to claim 3, wherein the temperature of the electrode supporting the substrate in the discharge space is in the range of -50 ° C to 0 ° C with respect to the glass transition temperature of the substrate.

(Claim 5)
5. The temperature of the mixed gas containing the discharge gas and the thin film forming gas in the discharge space is near or above the crystallization temperature of the thin film formed on the substrate. A method for forming a thin film according to 1.

  The present invention makes it possible to form highly functional thin films with high performance with high productivity. In addition to high-quality amorphous thin films, extremely high-quality thin films with crystallinity can A process that can be formed on a weak substrate is obtained.

  Next, the best mode for carrying out the present invention will be described, but the present invention is not limited thereto.

  The inventors of the present invention maintain the substrate itself in the vicinity of its glass transition temperature, desirably lower than that, increase the temperature of only the extreme surface of the substrate by increasing the plasma gas temperature, and improve the quality of the substrate without deformation. We found that a dense film can be formed. And it discovered that the effect of plasma CVD performed under atmospheric pressure was more remarkable than plasma CVD performed under vacuum.

However, if the gas temperature is raised with the discharge gas and the reactive gas containing the thin film forming gas mixed, the decomposition of the thin film forming gas (raw material gas) in the mixed gas begins, and particles are generated before reaching the discharge space. End up.
As a result of diligent examination, a reactive gas containing a discharge gas and a thin film forming gas was separated and supplied, and only the discharge gas was supplied at a high temperature, and the reactive gas was supplied below the thermal decomposition temperature of the thin film forming gas. By mixing in the space or immediately before it, it becomes possible to increase the temperature only on the surface of the substrate and form a dense film.

  In addition, in order to keep the substrate itself at or near its glass transition temperature, the temperature of the electrode supporting the substrate is controlled within a range of ± 50 ° C with respect to the glass transition temperature in the discharge space. By doing so, it is possible to prevent deformation other than the surface of the base electrode.

  The thin film forming method of the present invention includes a discharge space in which an application electrode and a ground electrode are arranged to face each other, voltage application means for applying a voltage to the application electrode and the ground electrode, and a thin film forming gas in the discharge space. The gas containing the discharge gas and the thin film forming gas is supplied to the discharge space under the atmospheric pressure or a pressure near the atmospheric pressure by the reactive gas and the gas introducing means for introducing the discharge gas. A thin film forming method for performing surface treatment of the substrate by exciting the reactive gas flowing into the discharge space to generate discharge plasma and exposing the substrate to the discharge plasma, The reactive gas and the discharge gas are separated and introduced separately into the discharge space, and the temperature of the mixed gas in the discharge space is in the range of 300 ° C. to 3000 ° C. A thin film forming method according to.

  The temperature of the mixed gas of the reactive gas containing the discharge gas and the thin film forming gas in the discharge space is more preferably 500 ° C. or higher and 1000 ° C. or lower.

  In order to set the temperature of the mixed gas as described above, for the discharge gas and the reactive gas (thin film forming gas) supplied separately, the temperature of the reactive gas is changed to the thermal decomposition temperature of the thin film forming gas in the reactive gas. In the following, the discharge gas is preferably supplied at a high temperature of 300 ° C. to 3000 ° C., for example, in order to set the temperature of the mixed gas in the discharge space to the above temperature range. It becomes possible to make a pole surface into high temperature.

  The discharge gas temperature is preferably 300 ° C. or higher, and desirably 500 ° C. or higher.

  Here, the extreme surface refers to a range of several nm from the substrate surface.

The thermal decomposition temperature of the thin film forming gas varies depending on the type of thin film to be formed, that is, the type of source gas. For example, tetraethoxysilane used for forming SiO ₂ is (230 ° C.), and titanium isopropoxide used for forming TiO ₂ is (280 ° C.).

However, since these thermal decomposition temperatures actually vary depending on the atmosphere, the thin film forming gas is preferably supplied after being diluted in an inert gas such as N ₂ , He, or Ar.

The thermal decomposition temperature of these thin film forming gases can be measured by a thermal analyzer (TG / DTA, DSC, etc.).
TG: Thermogravimetry (continuously detects and measures weight changes that occur when heat is applied to the sample), DTA: Differential thermal analyzer (when heat is applied to the sample and reference material (generally alumina)) The resulting temperature difference is measured as a function of temperature) and DSC: Differential Scanning Calorimeter (when the sample and reference material are heated, the difference in heat input to the sample and reference material is measured as a function of temperature) It can be measured by etc. In this invention, it measured using DSC.

For example, the thermal decomposition temperature is 400 ° C. for disilane (Si ₂ H ₆ ) used as the source gas for the SiGe thin film, and the thermal decomposition temperature> 1000 ° C. for germanium fluoride (GeF ₄ ).

  Even if it is supplied at a temperature lower than the thermal decomposition temperature, a high-temperature mixed gas (plasma) can be generated by mixing with the above-mentioned high-temperature discharge gas, so that a dense film can be formed efficiently. .

  Therefore, the required mixed gas temperature is determined by the film to be formed and the required film. Also, higher temperatures are required to obtain a crystallized film.

  As described above, by separately supplying each gas and individually setting the gas temperature of each gas, it is possible to ensure the mixed gas (plasma) temperature in the discharge space necessary for obtaining a dense film. In addition, by providing a temperature control system inside the piping that supplies the reactive gas, the temperature can be controlled to be equal to or lower than the thermal decomposition temperature of the thin film forming gas in the reactive gas, and generation of particles can be suppressed. In addition, setting the reactive gas temperature to a temperature higher than the temperature corresponding to the saturated vapor pressure of the thin film forming gas also prevents condensation of the thin film forming gas on the electrode surface, generation of deposits, and generation of decomposition products. As a result, it is preferable in order to achieve uniform film formation.

  In addition, in order to keep the substrate itself in the vicinity of the glass transition temperature, or below, the temperature of the electrode supporting the substrate in the discharge space is controlled in the vicinity of ± 50 ° C. with respect to the glass transition temperature. It is preferable not to cause deformation except for the surface of the substrate. That is, by controlling the temperature of the electrode that supports and contacts the substrate to the above temperature, the temperature of the substrate itself is prevented from rising excessively. Although the temperature of the said electrode should just be the temperature of the glass transition temperature vicinity called the range of +/- 50 degreeC with respect to the glass transition temperature of a base material, it is Tg-50 degreeC lower than this with respect to glass transition temperature (Tg). The range of ~ Tg is more preferable.

(Embodiment of the Invention)
Embodiments of an atmospheric pressure plasma processing method and an atmospheric pressure plasma processing apparatus according to the present invention will be described below with reference to the drawings, but the present invention is not limited thereto. In addition, the following description may include affirmative expressions for terms and the like, but it shows preferred examples of the present invention and limits the meaning and technical scope of the terms of the present invention. It is not a thing.

  The atmospheric pressure plasma processing apparatus of the present invention can form various high-performance thin films on a substrate, for example, an electrode film, a dielectric protective film, a semiconductor film, a transparent conductive film, an electrochromic film, a fluorescent film, Superconducting film, dielectric film, solar cell film, antireflection film, abrasion resistant film, optical interference film, reflection film, antistatic film, conductive film, antifouling film, hard coat film, undercoat film, barrier film, Can be used for forming electromagnetic shielding film, infrared shielding film, ultraviolet absorbing film, lubricating film, shape memory film, magnetic recording film, light emitting element film, biocompatible film, corrosion resistant film, catalyst film, gas sensor film, decorative film, etc. .

  FIG. 1 is a cross-sectional view showing an example of a gas introduction part and an electrode part of a film forming apparatus used in the thin film forming method of the present invention.

  In FIG. 1, 1 is a base material which forms a thin film. The substrate that can be used in the present invention is not particularly limited as long as a thin film can be formed on the surface thereof, such as a substrate such as glass or resin, a film-like material, or a three-dimensional material such as a lens shape.

  The material constituting the substrate is not particularly limited, but a resin can be preferably used because it is under atmospheric pressure or near atmospheric pressure, and high temperature is limited to the extreme surface.

  For example, when the thin film according to the present invention is an antireflection film, the substrate is preferably a cellulose ester such as a cellulose triacetate film, polyester, polycarbonate, polystyrene, and further gelatin, polyvinyl alcohol (PVA), acrylic on these. A resin, polyester resin, cellulose-based resin, or the like can be used. Further, these base materials have an antiglare layer or a clear hard coat layer coated with a resin layer formed by polymerizing a component containing an ethylenically unsaturated monomer on a support, a back coat layer, an antistatic layer. Can be used.

  As the above support (also used as a base material), specifically, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose acetate butyrate film, Cellulose acetate propionate film, cellulose acetate phthalate film, cellulose triacetate, cellulose ester film such as cellulose nitrate, or derivatives thereof, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene series Film, polycarbonate film, norbornene resin film, polymethylpen Film, polyetherketone film, polyimide film, polyethersulfone film, polysulfone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film, polymethylmethacrylate film, acrylic film or polyarylate film Can be mentioned.

  These materials can be used alone or in combination as appropriate. Among these, commercially available products such as ZEONEX (manufactured by Nippon Zeon Co., Ltd.) and ARTON (manufactured by Nippon Synthetic Rubber Co., Ltd.) can be preferably used. Furthermore, even for materials with a large intrinsic birefringence, such as polycarbonate, polyarylate, polysulfone, and polyethersulfone, conditions such as solution casting and melt extrusion, as well as stretching conditions in the longitudinal and lateral directions are set as appropriate. Can be obtained. Moreover, the support body which concerns on this invention is not limited to said description. A film thickness of 10 to 1000 nm is preferably used.

  In the present invention, when the thin film provided on the substrate is an antireflection film, it is preferable to use a cellulose ester film as the support according to the present invention, because a laminate having a low reflectance can be obtained. . From the viewpoint of preferably obtaining the effects described in the present invention, as the cellulose ester, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable, and among them, cellulose acetate butyrate and cellulose acetate propionate are preferably used.

  In accordance with the glass transition temperature Tg of the film material used as the base material, it is preferable that the temperature of the electrode that transports and contacts the base material is controlled to be in the vicinity thereof.

  The glass transition temperature Tg of a typical material is determined by measuring with a differential scanning calorimeter. For example, when a sample film 10 mg is heated at 20 ° C./min in a helium-nitrogen stream, The arithmetic average temperature of the temperature that starts to deviate and the temperature that newly returns to the baseline, or when an endothermic peak appears in Tg, the temperature that shows the maximum value of this endothermic peak is defined as Tg.

  For example, the glass transition temperature Tg of a polyester film is approximately 90 ° C. or more and 200 ° C. or less, although it varies depending on the production method such as the degree of polymerization and additives of the chip as the material, and the degree of crystallization.

  In FIG. 1, the application electrodes 2a and 2b are high-voltage application electrodes, respectively. The application electrodes 2a and 2b are obtained by coating the surfaces of the metal bases 3a and 3b with dielectrics 4a and 4b. It is preferable to have a cooling means for the application electrodes 2a and 2b so that the inside can be cooled by cooling water or the like.

  On the other hand, at a position facing the application electrodes 2a and 2b, a ground electrode 5 for holding the base material is disposed as an electrode which is transported in contact with the base material. The ground electrode 5 is preferably a metal base 7 coated with a dielectric 6.

  In each of the electrodes, examples of the metal matrix (3a, 3b, 7) include metals such as silver, platinum, stainless steel, aluminum, and iron. Stainless steel is preferable from the viewpoint of processing.

  The dielectric (4a, 4b, 6) is preferably an inorganic material, and the dielectric is preferably subjected to a sealing treatment with a silicon compound that is cured by a sol-gel reaction after thermal spraying of alumina ceramics.

Dielectrics include inorganic materials such as silicate glass, borate glass, phosphate glass, germanate glass, tellurite glass, aluminate glass, vanadate glass, etc. Can be used. Of these, borate glass is easy to process. It is also preferable to use a highly heat-resistant ceramic with high hermeticity by thermal spraying. Examples of the ceramic material include alumina-based, zirconia-based, silicon nitride-based, and silicon carbide-based ceramics. Among them, alumina-based ceramics are preferable, and among alumina-based ceramics, Al ₂ O ₃ is particularly preferable. . The thickness of the alumina ceramic is preferably about 1 mm, and the volume resistivity is preferably 10 ⁸ Ω · cm or more.

  The ceramic is preferably sealed with an inorganic material, whereby the durability of the electrode can be improved. After coating the alumina-based ceramics and applying a sol that is a sealant, a silicon compound that is cured by a sol-gel reaction (preferably alkoxysilane), and then gelled and cured, Ceramic sealing can be performed by forming a strong three-dimensional bond to form a silicon oxide having a uniform structure.

  Moreover, it is preferable to perform energy treatment in order to promote the sol-gel reaction. By applying energy treatment to the sol, a three-dimensional bond of metal-oxygen-metal can be promoted. The energy treatment is preferably plasma treatment, heat treatment at 200 ° C. or lower, and UV treatment.

  In a method of manufacturing an electrode by coating a dielectric on a metal base material at a high temperature, at least the dielectric on the side in contact with the substrate is polished and further, thermal expansion between the metal base material and the dielectric of the electrode It is necessary to make the difference as small as possible. Therefore, in the manufacturing method, the surface of the base material is lined with an inorganic material by controlling the amount of bubbles mixed as a layer capable of absorbing stress. It is preferable that the glass is obtained by a melting method, and the amount of bubbles mixed in the lowermost layer in contact with the conductive metal base material is set to 20 to 30% by volume, and the subsequent layer and the subsequent layers are set to 5% by volume or less, thereby being dense and A good electrode without cracks and the like can be produced.

  In addition, as a method according to the present invention for coating the metal base material of the electrode with a dielectric material, ceramic spraying is performed precisely to a porosity of 10% by volume or less, and sealing treatment is performed with an inorganic material that is cured by a sol-gel reaction. In order to promote the sol-gel reaction, heat curing and UV curing are good. Further, diluting the sealing liquid and repeating coating and curing several times in succession further improves mineralization and deteriorates. A dense electrode without any defects can be formed.

  FIG. 2 shows an example of a high voltage application electrode that can be used in the present invention. FIG. 2 is a perspective view showing an example of an electrode fixed in a prismatic shape. When the counter electrode for applying a high voltage is taken as an example, the fixed application electrodes 2a and 2b and the hollow metal bases 3a and 3b are formed. The stainless steel pipe is composed of a combination in which ceramics are thermally sprayed and then sealed with a dielectric material 4a, 4b that is sealed with an inorganic material.

  In the discharge space formed between the application electrodes 2a and 2b and the ground electrode 5 for holding the base material, the temperature of the ground electrode 5 that contacts and supports the base material is ± 50 with respect to its glass transition temperature. It is preferable that the temperature is adjusted in the range of ° C., particularly preferably in the range of glass transition temperature −50 ° C. to glass transition temperature (Tg). As a result, the plasma temperature in the discharge space is set in the above range, a dense film is formed, and the rise in the temperature of the base material is suppressed, whereby the deformation of the resin base material can be suppressed.

  If the temperature is much higher than the glass transition temperature, the deformation of the substrate becomes a problem. On the other hand, if the temperature is too lower than the glass transition temperature, the mixed gas in the discharge space is obtained in order to obtain a dense film. High temperatures (300 ° C. or higher and 300 ° C. or lower) are difficult to obtain. Also, from the viewpoint of crystallization of a thin film formed on a substrate, a sufficient surface temperature cannot be obtained, which is not preferable.

  Therefore, the mixed gas (plasma) temperature required in the discharge space requires the high temperature (300 ° C. or more and 300 ° C. or less) in order to obtain a dense film. The temperature of (plasma) is more preferable if it is near or above the crystallization temperature of the thin film formed on the substrate.

The required mixed gas temperature is appropriately changed according to the desired film and its film quality. For example, as a film having a high barrier performance, there is a SiO ₂ film. When the film is formed, if the temperature is 300 ° C. or higher, the film becomes considerably dense, and a film having a very high barrier property is formed. The On the other hand, in the case of an ITO film, if the temperature is 300 ° C. or higher, desirably, the crystallization temperature or higher, that is, 400 ° C. or higher, crystallinity is manifested from amorphous, so that a very low resistance film can be formed.
Further, regarding the TiO ₂ film, a crystalline thin film having an anatase structure is formed by setting the temperature to 300 ° C. or higher, preferably 500 ° C. or higher, and preferably a thin film having a rutile structure is formed by setting the temperature to 700 ° C. or higher. Is done.

  The required crystallization temperature of the film is to heat a film formed on a heat-resistant substrate such as a silicon substrate and analyze the film using an X-ray diffraction method to see whether a crystallized film is formed. Come. The crystallization temperature measured by this method is, for example, 150 ° C. for the ITO film, and the crystallization temperature of TiO 2 is 400 ° C. for the anatase type and 600 ° C. for the rutile type. Since the crystallization temperature may be slightly different due to the influence of the purity and density of the film, the mixed gas temperature is preferably close to the crystallization temperature (± 100 ° C., preferably ± 50 ° C.), and more than the crystallization temperature. More preferably.

  In FIG. 1, reference numeral 8 denotes a high frequency power source for applying a high frequency voltage between the application electrodes 2a and 2b and the earth electrode 5, and the applied voltage preferably exceeds 100 kHz. Preferably, the upper limit value is 150 MHz or less. The high-frequency power source that can be used in the present invention is not particularly limited. For example, the high-frequency power source (200 kHz), the same (800 kHz), the same (2 MHz) manufactured by Pearl Industry, the high frequency power source (13.56 MHz) manufactured by JEOL, A high-frequency power source (150 MHz) manufactured by Pearl Industry can be used.

Reference numeral 9 denotes a ground, and the second electrode 5 is grounded to the ground 9. Moreover, the discharge output of the voltage supplied between the said electrodes is 1 W / cm < ² > or more, Preferably it is 1-50 W / cm < ² >. By setting the discharge output within the range specified above, the plasma density of the discharge plasma can be increased.

  In FIG. 1, 10 is a gas introduction part. The gas introduction part 10 has a discharge gas passage 11 at the center thereof and reactive gas passages 12a and 12b around it. The discharge gas passage 11 and the reactive gas passages 12a and 12b are separated by discharge gas passage walls 14a and 14b, and the reactive gas passages 12a and 12b are separated from the outside by the reactive gas passage walls 15a and 15b.

  The structures of the discharge gas passage 11 as the discharge gas introduction means and the reactive gas passages 12a and 12b as the reactive gas introduction means are configured so that the respective gases are not mixed before being introduced into the discharge space. There is no particular limitation. For example, it may be a slit-like form separated by straight passage walls 14a, 14b, 15a, 15b, or a structure in which cylinders having different inner diameters are combined, but from the viewpoint of simplicity and ease of temperature control, The former is preferred. In the present invention, it is preferable to have temperature control means for controlling the temperature of the discharge gas passage walls 14a and 14b in order to heat the discharge gas. By controlling the temperature of the internal piping parts (reactive gas passage walls 14a, 14b) for supplying the discharge gas by the temperature control means, the temperature of the mixed gas in the discharge space can be set to a temperature of 300 ° C to 3000 ° C. It is preferable to control the temperature when the reactive gas is supplied to the discharge space.

  Accordingly, the discharge gas passage 11 is provided with heat retention control systems 13a and 13b as temperature control means for controlling the temperature to obtain the above-mentioned high-temperature gas.

  The heat insulation control system includes a temperature sensor unit, a heating unit, and a control unit, and based on the temperature detected by the temperature sensor, the temperature is raised by a heating medium incorporated in the discharge gas passage wall so as to obtain a desired temperature. Is what you do.

  As described above, for the rare gas and the inert gas, which are discharge gases, the reactive gas can be mixed with the thin film forming gas to generate discharge plasma at a high temperature in the above range. Apart from that, it is preferable to be heated to a relatively high temperature in the range of 300 ° C. to 3000 ° C. in advance.

  The material of the passage walls 14a, 14b, 15a, 15b constituting the discharge gas passage 11 or the reactive gas passages 12a, 12b according to the present invention has corrosion resistance and strength against each gas, and has a thermal conductivity. The material is not particularly limited as long as it is a high material, but ceramic is preferable.

  In the present invention, as described above, it is preferable that the reactive gas is maintained below the thermal decomposition temperature of the thin film forming gas. When the thin film forming gas component in the reactive gas (thin film forming gas) is, for example, tetraethoxysilane or the like, the thin film forming gas is thermally decomposed before being introduced into the discharge space by being controlled below this thermal decomposition temperature, Try to suppress the generation of particles. Therefore, it is preferable that the temperature of the thin film forming gas introduction passage is adjusted so as not to exceed the thermal decomposition temperature of the thin film forming component. On the other hand, it is preferable to set the temperature higher than the temperature indicating the saturated vapor pressure in the thin film forming gas concentration at the time of supplying the reactive gas, because condensation of the component can be prevented. For this reason, although not shown, another heat retention control system is also provided in the reactive gas passage so that the thin film forming component does not exceed the thermal decomposition temperature and also prevents condensation of the thin film forming component. Is provided.

  FIG. 3 is a schematic diagram showing another example of the overall configuration of the film forming apparatus used in the thin film forming method of the present invention.

  FIG. 3 includes a plasma discharge processing apparatus 30, a gas filling means 50, a voltage applying means 40, and an electrode temperature adjusting means 60. In FIG. 3, plasma discharge is applied to the film-like substrate 1 using the application electrodes 2 a and 2 b and the ground electrode 5 fixed in opposition shown in FIG. 1 as the roll rotation electrode 25 and a plurality of prismatic fixed electrodes 36. Processing is performed. The base material 1 is unwound from an unillustrated original roll and conveyed, or is conveyed from the previous process, and air or the like accompanying the base material 1 by the nip roll 65 via the guide roll 64. While being cut and wound while being in contact with the roll rotation electrode 25, it is transferred between the plurality of prismatic fixed electrodes 36, passed through the nip roll 66 and the guide roll 67, and taken up by a winder (not shown). Or transfer to the next process. The reactive gas is flow-controlled by the gas supply means 50 with the reactive gas generated by the gas generator 51 and the discharge gas generated by the gas generator 81 with the discharge gas supply means 80, respectively. 1 is sent to the discharge space from the air supply port 52 having the configuration indicated by 1. The treated exhaust gas G ′ is discharged from the exhaust port 53. In the figure, only one gas introduction part 10a, 10b and exhaust port 53 are shown, but each prismatic fixed electrode 36 represents two sets of application electrodes shown in FIG. Next, the voltage applying means 40 applies a voltage to the prismatic fixed electrode 36 from the high frequency power source 41, and the roll rotating electrode 25 is grounded to generate discharge plasma. Although not shown in the figure, the same high-frequency voltage is supplied from the high-frequency power source 41 to the respective prismatic fixed electrodes 36 by the voltage applying means 40. The roll rotating electrode 25 or the prismatic fixed electrode 36 can be fed to the electrode by heating or cooling the medium using electrode temperature adjusting means 60 and 70, respectively. The medium whose temperature is adjusted by the electrode temperature adjusting means 60, 70 is adjusted from the inside of the roll rotating electrode 25 or the prismatic fixed electrode 36 via the pipes 61, 71 by the liquid feed pump P.

  In particular, as described above, the temperature of the roll rotating electrode 25 that contacts and transports the base material is controlled by the electrode temperature adjusting means 70 in the vicinity of the glass transition temperature of the base material 1. preferable. A gas such as air can be used as the heat medium, but insulating materials such as distilled water and oil such as silicon oil are preferably used. Although the temperature of a base film changes with process conditions, the temperature of room temperature-350 degreeC is normally used. During the plasma discharge treatment, it is desired to control the temperature inside the rotating electrode using a roll so that the temperature unevenness of the base film in the width direction or the longitudinal direction does not occur as much as possible.

  The gas used in the present invention is basically a mixed gas of an inert gas and a reactive gas for forming a thin film, although it varies depending on the type of thin film to be provided on the substrate. It is preferable to contain 0.01-10 volume% of reactive gas with respect to mixed gas. As the thickness of the thin film, a thin film in the range of 1 to 1000 nm is obtained.

  Examples of the inert gas include Group 18 elements of the periodic table, specifically helium, neon, argon, krypton, xenon, radon, etc. In order to obtain the effects described in the present invention, helium Argon is preferably used.

  The reactive gas which concerns on this invention is gas containing the thin film formation gas (raw material gas) containing the element used as the raw material of a thin film.

  The thin film forming gas varies depending on the type of thin film to be provided on the substrate, but for example, an organic fluorine compound can be used to form a low refractive index layer or an antifouling layer useful for an antireflection layer, By using a silicon compound, a low refractive index layer or a gas barrier layer useful for an antireflection layer or the like can be formed. Further, by using an organometallic compound containing a metal such as Ti, Zr, Sn, Si or Zn, a metal oxide layer or a metal nitride layer can be formed. A useful medium refractive index layer or high refractive index layer can be formed, and a conductive layer or an antistatic layer can also be formed. Preferred examples of the thin film forming gas include organic fluorine compounds and metal compounds.

  As the metal compound of the source gas, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Cr, Co, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge , Hf, Hg, Ho, In, Ir, La, Li, LuMg, Mn, Mo, Na, Nb, Nd, Ni, Pb, Pm, Pr, Pt, Rb, Rh, Sb, Sc, Se, Si, Sn , Sr, Ta, Tb, Ti, Tl, Tm, V, W, Y, Yb, Zn, Zr, and other metal compounds or organometallic compounds.

  Among these, examples of the silicon compound include alkyl silanes such as dimethylsilane and tetramethylsilane; silicon such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, and ethyltriethoxysilane. Examples include organosilicon compounds such as alkoxides; silicon hydrogen compounds such as monosilane and disilane; halogenated silicon compounds such as dichlorosilane, trichlorosilane, and tetrachlorosilane; and other organosilanes.

  Examples of metal compounds other than silicon as a thin film forming gas (raw material gas) include organic metal compounds, metal halide compounds, metal hydrogen compounds, and the like. As the organic component of the organometallic compound, an alkyl group, an alkoxide group, and an amino group are preferable, and tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, tetradimethylaminotitanium, and the like can be preferably exemplified. In addition, examples of the metal halide compound include titanium dichloride, titanium trichloride, and titanium tetrachloride, and examples of the metal hydrogen compound include monotitanium and dititanium.

  The reactive gas according to the present invention may contain a reaction promoting gas depending on the type of thin film forming gas (raw material gas) contained in the reactive gas. Examples of the reaction promoting gas include oxygen gas, hydrogen gas, water vapor, hydrogen peroxide gas, carbon monoxide gas, carbon dioxide gas, nitrogen gas, ozone gas, ammonia, and nitrogen oxide.

  For example, at least selected from zinc acetylacetonate, triethylindium, trimethylindium, diethylzinc, dimethylzinc, etraethyltin, etramethyltin, di-n-butyltin diacetate, tetrabutyltin, tetraoctyltin and the like as the reactive gas A reactive gas containing one organometallic compound can be used to form a metal oxide layer useful as a middle refractive index layer of a conductive film, an antistatic film, or an antireflection film.

Moreover, by using a fluorine-containing compound gas, a water-repellent film can be obtained in which a fluorine-containing group is formed on the surface of the substrate to reduce the surface energy and obtain a water-repellent surface. Examples of the fluorine element-containing compound include fluorine / carbon compounds such as hexafluoropropylene (CF ₃ CFCF ₂ ) and octafluorocyclobutane (C ₄ F ₈ ). From the viewpoint of safety, it is preferable to use propylene hexafluoride or cyclobutane octafluoride that does not generate hydrogen fluoride, which is a harmful gas.

  Moreover, a hydrophilic polymer film can be deposited by performing the treatment in an atmosphere of a monomer having a hydrophilic group and a polymerizable unsaturated bond in the molecule. Examples of the hydrophilic group include a hydroxyl group, a sulfonic acid group, a sulfonate group, a primary or secondary or tertiary amino group, an amide group, a quaternary ammonium base, a carboxylic acid group, and a carboxylic acid group. Can be mentioned. Similarly, a hydrophilic polymer film can be deposited using a monomer having a polyethylene glycol chain.

  Examples of the monomer include acrylic acid, methacrylic acid, acrylamide, methacrylamide, N, N-dimethylacrylamide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, sodium styrenesulfonate, allyl alcohol, allylamine, polyethylene. Examples thereof include glycol dimethacrylic acid ester and polyethylene glycol diacrylic acid ester, and at least one of them can be used.

  Further, by using a reactive gas containing an organic fluorine compound, a silicon compound, or a titanium compound, the low refractive index layer or the high refractive index layer of the antireflection film can be provided.

  As the organic fluorine compound, a fluorocarbon gas, a fluorinated hydrocarbon gas, or the like is preferably used. Examples of the fluorocarbon gas include carbon tetrafluoride and carbon hexafluoride, specifically, tetrafluoromethane, tetrafluoroethylene, hexafluoropropylene, octafluorocyclobutane, and the like. Examples of the fluorinated hydrocarbon gas include difluoromethane, tetrafluoroethane, tetrafluoropropylene, and trifluoride propylene.

  Furthermore, a halogenated fluoride compound such as trichloromethane monochloride, methane difluoride methane, or cyclobutane tetrachloride, or a fluorine-substituted product of an organic compound such as alcohol, acid, or ketone may be used. Yes, but not limited to these. Moreover, these compounds may have an ethylenically unsaturated group in the molecule. The above compounds may be used alone or in combination.

  When the organic fluorine compound described above is used in the mixed gas, the content of the organic fluorine compound in the mixed gas is 0.1 to 10% by volume from the viewpoint of forming a uniform thin film on the substrate by discharge plasma treatment. Although it is preferable, it is 0.1-5 volume% more preferably.

  Further, when the organic fluorine compound is a gas at normal temperature and pressure, it can be used as it is as a component of the mixed gas, so that the method of the present invention can be performed most easily. However, when the organic fluorine compound is liquid or solid at normal temperature and normal pressure, it may be vaporized by a method such as heating or decompression, or it may be dissolved in an appropriate solvent.

  When using the above-described titanium compound in the mixed gas, the content of the titanium compound in the mixed gas is 0.01 to 10% by volume from the viewpoint of forming a uniform thin film on the substrate by discharge plasma treatment. Although it is preferable, 0.01 to 1 volume% is more preferable.

  Moreover, the hardness of a thin film can be remarkably improved by containing 0.1-10 volume% of hydrogen gas in the said mixed gas.

  In addition, by containing 0.01 to 5% by volume of a component selected from oxygen, ozone, hydrogen peroxide, carbon dioxide, carbon monoxide, and hydrogen in the mixed gas, the reaction is promoted and is dense and of high quality. A thin film can be formed.

  The reactive gas may contain a reaction promoting gas depending on the type of raw material gas contained in the reactive gas. Examples of the reaction promoting gas include oxygen gas, hydrogen gas, water vapor, hydrogen peroxide gas, carbon monoxide gas, carbon dioxide gas, ozone gas, ammonia, and nitrogen oxide.

  These reaction promoting gases may be contained in the discharge gas according to the type of the raw material gas contained in the reactive gas, and this is preferable because it can increase the reaction gas temperature.

  As the silicon compounds and titanium compounds described above, metal hydrides and metal alkoxides are preferable from the viewpoint of handling, and metal alkoxides are preferably used because they are not corrosive, do not generate harmful gases, and have little contamination in the process. It is done.

  Further, in order to introduce the silicon compound and the titanium compound described above between the electrodes which are the discharge spaces, both of them may be in the state of gas, liquid or solid 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, decompression or ultrasonic irradiation. When a silicon compound or a titanium compound is vaporized by heating, a metal alkoxide that is liquid at room temperature and has a boiling point of 200 ° C. or lower, such as tetraethoxysilane or tetraisopropoxytitanium, is preferably used for forming the antireflection film. The metal alkoxide may be used after being diluted with a solvent. As the solvent, an organic solvent such as methanol, ethanol, n-hexane, or a mixed solvent thereof can be used. Since these diluted solvents are decomposed into molecular and atomic forms during the plasma discharge treatment, the influence on the formation of the thin film on the substrate, the composition of the thin film, etc. can be almost ignored.

  Examples of the silicon compound described above include organic metal compounds such as dimethylsilane and tetramethylsilane, metal hydrogen compounds such as monosilane and disilane, metal halogen compounds such as silane dichloride and silane trichloride, tetramethoxysilane, and tetraethoxy. It is preferable to use alkoxysilane such as silane or dimethyldiethoxysilane, organosilane, or the like, but the invention is not limited to these. Moreover, these can be used in combination as appropriate.

  When the silicon compound described above is used in the mixed gas, the content of the silicon compound in the mixed gas is 0.01 to 10% by volume from the viewpoint of forming a uniform thin film on the substrate by discharge plasma treatment. Although it is preferable, 0.01 to 1 volume% is more preferable.

  Examples of the titanium compounds described above include organometallic compounds such as tetradimethylaminotitanium, metal hydrogen compounds such as monotitanium and dititanium, metal halogen compounds such as titanium dichloride, titanium trichloride, and titanium tetrachloride, tetraethoxy titanium, tetra Metal alkoxides such as isopropoxy titanium and tetrabutoxy titanium are preferably used, but are not limited thereto.

  Next, an atmospheric pressure plasma processing method using the atmospheric pressure plasma processing apparatus shown in FIG. 1 will be described.

  The substrate 1 is conveyed between the application electrodes 2a and 2b and the substrate holding ground electrode 5 by a conveying means such as a belt conveyor (not shown). Here, after the base material is installed, the ground electrode 5 for holding the base material moves in parallel during film formation.

  On the other hand, a discharge gas is introduced into the discharge gas passage 11 and a reactive gas is introduced into the reactive gas passages 12a and 12b. At this time, the discharge gas passage walls 14a and 14b are heated by the heat retention control systems 13a and 13b as necessary. Each introduced gas is pushed out to each newly introduced gas and introduced between the application electrodes 2a, 2b and the earth electrode 5, and the application electrodes 2a, 2b and the earth electrode existing under a pressure near atmospheric pressure. A high frequency voltage is applied between the five by a high frequency power source 8 to generate discharge plasma. The surface treatment of the base material 1 that has been transported by the belt conveyor is performed with the generated discharge plasma, and the base material 1 that has been subjected to the surface treatment is placed between the applied electrodes 2a and 2b and the ground electrode 5 by the belt conveyor. It is transported to.

  In the above thin film forming method, a rare gas such as helium or argon is used as a discharge gas, but the present invention can also be applied to a method using a cheaper gas such as nitrogen as a discharge gas.

  In a gas such as nitrogen, which has a high discharge starting electric field strength and is difficult to obtain a stable discharge under a conventional high frequency electric field, the first high frequency electric field and the second high frequency electric field are superimposed in the discharge space, and the discharge is performed. It is preferable to use the method of making it.

As the discharge condition of the case, the discharge space, wherein the first superimposing a high frequency electric field and the second high frequency electric field, said first high frequency electric field and the second than the frequency omega ₁ of the high-frequency electric field of a frequency omega ₂ And the relationship between the first high-frequency electric field strength V ₁ , the second high-frequency electric field strength V _2, and the discharge starting electric field strength IV is:
V ₁ ≧ IV> V ₂
Or V ₁ > IV ≧ V ₂ is satisfied,
The power density of the second high frequency electric field is 1 W / cm ² or more.

  High frequency refers to one having a frequency of at least 0.5 kHz.

High frequency electric field to be superimposed, if are both sine wave becomes a first high-frequency electric field of a frequency omega ₁ and the frequency omega higher than ₁ second high-frequency electric field of a frequency omega ₂ and the superposed component, its waveform frequency A sine wave having a higher frequency ω ₂ is superimposed on the sine wave of ω ₁ , resulting in a sawtooth waveform.

  The strength of the electric field at which discharge starts is the lowest electric field intensity that can cause discharge in the discharge space (electrode configuration, etc.) and reaction conditions (gas conditions, etc.) used in the actual thin film formation method. The discharge start electric field strength varies somewhat depending on the type of gas supplied to the discharge space, the dielectric type of the electrode, or the distance between the electrodes, but is controlled by the discharge start electric field strength of the discharge gas in the same discharge space.

  By applying a high-frequency electric field as described above to the discharge space, it is presumed that a discharge capable of forming a thin film is generated and high-density plasma necessary for forming a high-quality thin film can be generated.

  What is important here is that such a high-frequency electric field is applied to the opposing electrodes, that is, applied to the same discharge space.

  Although superposition of continuous waves such as sine waves is preferable, the present invention is not limited to this, and both pulse waves may be used, one may be continuous waves and the other may be pulse waves. Further, it may have a third electric field.

As a specific method for applying the high-frequency electric field of the present invention to the same discharge space, a first high-frequency electric field having a frequency ω ₁ and an electric field strength V ₁ is applied to the first electrode constituting the counter electrode. An atmospheric pressure plasma discharge treatment apparatus is used in which a first power source is connected, and a second power source is connected to the second electrode to apply a second high-frequency electric field having a frequency ω ₂ and an electric field strength V ₂ .

  The atmospheric pressure plasma discharge treatment apparatus includes a gas supply unit that supplies a discharge gas and a thin film forming gas between the counter electrodes. Furthermore, it is preferable to have an electrode temperature control means for controlling the temperature of the electrode.

  Further, it is preferable to connect the first filter to the first electrode, the first power source or any of them, and connect the second filter to the second electrode, the second power source or any of them, The first filter facilitates the passage of the first high-frequency electric field current from the first power source to the first electrode, grounds the second high-frequency electric field current, and the second filter from the second power source to the first power source. It makes it difficult to pass the current of the high frequency electric field. On the other hand, the second filter makes it easy to pass the current of the second high-frequency electric field from the second power source to the second electrode, grounds the current of the first high-frequency electric field, and the second power from the first power source. A power supply having a function of making it difficult to pass the current of the first high-frequency electric field to the power supply is used. Here, being difficult to pass means that it preferably passes only 20% or less of the current, more preferably 10% or less. On the contrary, being easy to pass means preferably passing 80% or more of the current, more preferably 90% or more.

  Furthermore, it is preferable that the first power source of the atmospheric pressure plasma discharge processing apparatus of the present invention has a capability of applying a higher frequency electric field strength than the second power source.

  Here, the high frequency electric field strength (applied electric field strength) and the discharge starting electric field strength referred to in the present invention are those measured by the following method.

Measuring method of high frequency electric field strengths V ₁ and V ₂ (unit: kV / mm):
A high-frequency voltage probe (P6015A) is installed in each electrode section, and the output signal of the high-frequency voltage probe is connected to an oscilloscope (Tektronix, TDS3012B), and the electric field strength is measured.

Measuring method of electric discharge starting electric field intensity IV (unit: kV / mm):
A discharge gas is supplied between the electrodes, the electric field strength between the electrodes is increased, and the electric field strength at which discharge starts is defined as a discharge starting electric field strength IV. The measuring instrument is the same as the high frequency electric field strength measurement.

  The positional relationship between the high-frequency voltage probe used for the measurement and the oscilloscope is shown in FIG.

  By adopting the discharge conditions specified in the present invention, even a discharge gas having a high discharge starting electric field strength, such as nitrogen gas, can start discharge, maintain a high density and stable plasma state, and form a high-performance thin film. It can be done.

When the discharge gas is nitrogen gas by the above measurement, the discharge start electric field strength IV (1/2 V _pp ) is about 3.7 kV / mm. Therefore, in the above relationship, the first high frequency electric field strength is By applying V ₁ ≧ 3.7 kV / mm, the nitrogen gas can be excited to be in a plasma state.

  Here, the frequency of the first power source is preferably 200 kHz or less. The electric field waveform may be a continuous wave or a pulse wave. The lower limit is preferably about 1 kHz.

  On the other hand, the frequency of the second power source is preferably 800 kHz or more. The higher the frequency of the second power source, the higher the plasma density, and a dense and high-quality thin film can be obtained. The upper limit is preferably about 200 MHz.

  The application of a high frequency electric field from such two power sources is necessary to start the discharge of a discharge gas having a high discharge start electric field strength by the first high frequency electric field, and the high frequency of the second high frequency electric field. In addition, it is an important point of the present invention to form a dense and high-quality thin film by increasing the plasma density with a high power density.

  Also, by increasing the output density of the first high-frequency electric field, the output density of the second high-frequency electric field can be improved while maintaining the uniformity of discharge. Thereby, a further uniform high-density plasma can be generated, and a further improvement in film formation speed and an improvement in film quality can be achieved.

  In the atmospheric pressure plasma discharge processing apparatus used in the present invention, the first filter facilitates passage of the current of the first high-frequency electric field from the first power source to the first electrode, and grounds the current of the second high-frequency electric field. Thus, it is difficult to pass the current of the second high-frequency electric field from the second power source to the first power source. On the other hand, the second filter makes it easy to pass the current of the second high-frequency electric field from the second power source to the second electrode, grounds the current of the first high-frequency electric field, and the second power from the first power source. The current of the first high-frequency electric field to the power supply is made difficult to pass. In the present invention, any filter having such properties can be used without limitation.

  For example, as the first filter, a capacitor of several tens of pF to several tens of thousands of pF or a coil of about several μH can be used depending on the frequency of the second power source. As the second filter, a coil of 10 μH or more is used according to the frequency of the first power supply, and it can be used as a filter by grounding through these coils or capacitors.

  As described above, the atmospheric pressure plasma discharge treatment apparatus used in the present invention discharges between the counter electrodes, puts the gas introduced between the counter electrodes into a plasma state, and places the gas between the counter electrodes or between the electrodes. By exposing the substrate to be transferred to the plasma state gas, a thin film is formed on the substrate. As another method, the atmospheric pressure plasma discharge treatment apparatus discharges between the counter electrodes similar to the above, excites the gas introduced between the counter electrodes or puts it in a plasma state, and excites or jets the gas outside the counter electrode. There is a jet type apparatus that blows out a plasma gas and exposes a substrate (which may be stationary or transferred) in the vicinity of the counter electrode to form a thin film on the substrate. .

  FIG. 4 is a cross-sectional view showing another example of the gas introduction part and the electrode part of the film forming apparatus used in the thin film forming method of the present invention.

  FIG. 4 shows a thin film deposition apparatus using a method in which the first high-frequency electric field and the second high-frequency electric field are superimposed and discharged in the discharge space, which is a preferable method when a gas such as nitrogen is used as the discharge gas. An example is shown.

  In FIG. 4, 1 is a base material which forms a thin film.

  The substrate is the same as described above.

  In FIG. 4, 2'a and 2'b are second electrodes, respectively, and the second electrode 2'a and the second electrode 2'b are formed of dielectrics 4a and 4b on the surfaces of the metal base materials 3a and 3b. It is a coated dielectric coated electrode. Although not shown, the electrode surface temperature can be controlled to be constant during the discharge by circulating cooling water or the like through the inside.

  On the other hand, a first electrode 5 'is disposed at a position facing the second electrodes 2'a and 2'b to form a discharge space. The discharge space is a space formed by the opposed first electrode and second electrode, and is a region where discharge is actually performed.

  The substrate 1 comes into contact with the surface of the first electrode 5 'on the second electrode 2'a, 2'b side and is conveyed in the direction of the arrow in the figure. The first electrode 5 ′ is a dielectric-covered electrode in which the dielectric 6 is coated on the metal base material 7 like the second electrodes 2 ′ a and 2 ′ b. Similarly, the first electrode 5 ′ has a structure in which cooling water or the like can be circulated therein to control the electrode surface temperature.

  The substrate 1 is conveyed in contact. The temperature of the first electrode 5 ′ is adjusted in the range of ± 50 ° C., particularly preferably in the range of glass transition temperature (Tg) −50 ° C. to glass transition temperature (Tg) with respect to the glass transition temperature of the substrate. This is the same as in FIG.

  In each of the above electrodes, the metal base materials (3a, 3b, 7) are the same as those described above, and examples thereof include metals such as silver, platinum, stainless steel, aluminum, and iron. It is preferable that

  The dielectrics 4a, 4b, and 6 are preferably inorganic compounds having a relative dielectric constant of 6 to 45, and examples of such dielectrics include ceramics such as alumina and silicon nitride, or silicate glass. And glass lining materials such as borate glass. Among these, a dielectric provided by spraying alumina is preferable.

  In the dielectric-coated electrode, as one of specifications to withstand high power, the dielectric has a porosity of 10% by volume or less, preferably 8% by volume or less. Preferably it is more than 0 volume% and 5 volume% or less. The porosity of the dielectric means a porosity that is penetrable in the thickness direction of the dielectric, and can be measured with a mercury porosimeter. In the examples described later, the porosity of the dielectric covered with the metal base material was measured with a mercury porosimeter manufactured by Shimadzu Corporation. High durability is achieved because the dielectric has a low porosity. Examples of the dielectric having such a void and a low void ratio include a high-density, high-adhesion ceramic spray coating by an atmospheric plasma spraying method described later. In order to further reduce the porosity, it is preferable to perform a sealing treatment.

  As another preferable specification of the dielectric-coated electrode, a dielectric is formed by a glass lining method using glass obtained by a melting method. In this case, the dielectric is made of two or more layers having different amounts of bubbles mixed in to enhance durability. As the amount of bubbles mixed in, the lowermost layer in contact with the metal base material is preferably 20 to 30% by volume, and the subsequent layers are preferably 5% by volume or less. The amount of bubbles mixed in can be calculated from the relationship between the intrinsic density of the glass itself and the density of the glass lining layer. As a method of controlling the amount of bubbles mixed into the glass, since the bubbles are originally mixed in the glass melt, deaeration is performed, but a desired value can be obtained by changing the degree of deaeration. A highly durable electrode can also be obtained by controlling the amount of bubbles mixed in and a dielectric material by a glass lining method provided in layers. In addition, the total thickness of the dielectric layer at this time is 0.5 mm or more and 2.0 mm or less, the film thickness of the lowermost layer is 0.1 mm or more, and the total film thickness after the next layer is 0.3 mm or more. Is preferred.

  In the dielectric-coated electrode, another preferred specification is that the heat-resistant temperature is 100 ° C. or higher. More preferably, it is 120 degreeC or more, Most preferably, it is 150 degreeC or more. The heat-resistant temperature refers to the highest temperature that can withstand normal discharge without breakdown. For such heat-resistant temperature, the dielectric provided by the above-mentioned ceramic spraying is applied, or a means for appropriately selecting a material within the range of the difference in linear thermal expansion coefficient between the conductive base material and the dielectric is appropriately combined. Is achievable.

In addition, in the dielectric-coated electrode according to the present invention, another preferable specification is a combination in which the difference in coefficient of linear thermal expansion between the dielectric and the metal base material is 10 × 10 ⁻⁶ / ° C. or less. It is preferably 8 × 10 ⁻⁶ / ° C. or less, more preferably 5 × 10 ⁻⁶ / ° C. or less, and further preferably 2 × 10 ⁻⁶ / ° C. or less. The linear thermal expansion coefficient is a well-known physical property value of a material.

As a combination of a metal base material and a dielectric that have a difference in linear thermal expansion coefficient within this range,
(1) Metal base material is pure titanium and dielectric is ceramic spray coating (2) Metal base material is pure titanium and dielectric is glass lining (3) Metal base material is titanium alloy and dielectric is ceramic spray coating (4) Metal base material is titanium alloy, dielectric is glass lining (5) Metal base material is stainless steel, dielectric is ceramic sprayed coating (6) Metal base material is stainless steel, dielectric is glass lining (7) Metal base material is ceramic and iron composite material, dielectric is ceramic spray coating (8) Metal base material is ceramic and iron composite material, dielectric is glass lining (9) Metal base material is composite of ceramic and aluminum The material is a ceramic sprayed coating. (10) The metal matrix is a composite material of ceramics and aluminum, and the dielectric is glass lining. From the viewpoint of the difference in linear thermal expansion coefficient, the above (1) to (4) and (7) to (10) are preferable.

  In the dielectric-coated electrode of the present invention, another preferred specification that can withstand high power is that the dielectric thickness 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.

  An example of a method for thermally spraying the metal base material with high density and high adhesion using ceramics as a dielectric is an atmospheric plasma spraying method. The atmospheric plasma spraying technique is a technique in which a fine powder such as ceramics, a wire, or the like is put into a plasma heat source and sprayed onto a base material to be coated as fine particles in a molten or semi-molten state to form a coating. A plasma heat source is a high-temperature plasma gas in which a molecular gas is heated to a high temperature, dissociated into atoms, and energy is given to emit electrons. This plasma gas injection speed is high, and since the sprayed material collides with the base material at a higher speed than conventional arc spraying or flame spraying, high adhesion strength and high density coating can be obtained. Specifically, reference can be made to a thermal spraying method for forming a heat shielding film on a high-temperature exposed member described in JP-A No. 2000-301655. According to this method, the porosity of the dielectric (ceramic sprayed film) to be coated can be 10% by volume or less, and further 8% by volume or less.

In order to further reduce the porosity of the dielectric, it is preferable to further seal the sprayed film such as ceramic with an inorganic compound. As the inorganic compound, a metal oxide is preferable, and among these, a compound containing silicon oxide (SiO _x ) as a main component is particularly preferable.

  The inorganic compound for sealing treatment is preferably formed by curing by a sol-gel reaction. In the case where the inorganic compound for sealing treatment contains a metal oxide as a main component, a metal alkoxide or the like is applied as a sealing liquid on the ceramic sprayed film and cured by a sol-gel reaction. When the inorganic compound is mainly composed of silica, it is preferable to use alkoxysilane as the sealing liquid.

  For promoting the sol-gel reaction, it is preferable to use energy treatment. Examples of the energy treatment include thermosetting (preferably 200 ° C. or less), UV irradiation, and the like. Furthermore, as a method of sealing treatment, when the sealing liquid is diluted and coating and curing are sequentially repeated several times, mineralization is further improved and a dense electrode without deterioration can be obtained.

When a ceramic sprayed coating is applied to a ceramic sprayed film using a metal alkoxide or the like of a dielectric-coated electrode as a sealing liquid, the content of the metal oxide after curing is 60 mol% or more when cured by a sol-gel reaction. Preferably there is. When alkoxysilane is used as the metal alkoxide of the sealing liquid, the content of SiO _x (x is 2 or less) after curing is preferably 60 mol% or more. The SiO _x content after curing is measured by analyzing the tomographic layer of the dielectric layer by XPS (X-ray Photoelectron Spectroscopy).

  Further, the surface roughness Rmax (JIS B 0601) of the electrode is reduced to 10 μm or less by a method such as polishing the dielectric surface of the dielectric coated electrode, so that the thickness of the dielectric and the gap between the electrodes are made constant. It can be maintained, the discharge state can be stabilized, distortion and cracking due to thermal shrinkage difference and residual stress can be eliminated, and durability can be greatly improved with high accuracy. The polishing finish of the dielectric surface is preferably performed at least on the dielectric in contact with the substrate.

In the thin film deposition apparatus of FIG. 4, a second high frequency power source 20 for applying a second high frequency voltage having a frequency ω ₂ and a voltage V ₂ is connected to the second electrodes 2′a and 2′b. A first high-frequency power source 21 that applies a first high-frequency voltage having a frequency ω ₁ and a voltage V ₁ is connected to one electrode 5 ′. The high frequency power supplies 20 and 21 are voltage applying means according to the present invention.

  The thin film deposition apparatus according to the present invention is not particularly limited as long as it is a high-frequency power source that can apply a high-frequency voltage between the first electrode and the second electrode.

  In the present invention, the high frequency means one having a frequency of at least 0.5 kHz.

  In the present invention, the atmospheric pressure or the pressure near atmospheric pressure is about 20 kPa to 110 kPa, and 93 kPa to 104 kPa is preferable in order to obtain a good effect described in the present invention.

As the first power source (high frequency power source) used in these thin film deposition apparatuses,
Applied power supply symbol Manufacturer Frequency A1 Shinko Electric 3kHz
A2 Shinko Electric 5kHz
A3 Kasuga Electric 15kHz
A4 Shinko Electric 50kHz
A5 HEIDEN Laboratory 100kHz *
A6 Pearl Industry 200kHz
And the like, and any of them can be preferably used. In addition, * mark is HEIDEN Laboratory impulse high frequency power supply (100 kHz in continuous mode).

As the second power source (high frequency power source),
Applied power symbol Manufacturer Frequency B1 Pearl industry 800 kHz
B2 Pearl Industry 2MHz
B3 Pearl Industry 13.56MHz
B4 Pearl Industry 27MHz
B5 Pearl Industry 150MHz
And the like, and any of them can be preferably used.

In the thin film deposition apparatus of the present invention, if a high frequency voltage can be applied between the first electrode and the second electrode, the high frequency voltage applied between the first electrode and the second electrode is the first frequency ω _1. And a component obtained by superimposing the voltage component of the second frequency ω ₂ higher than the first frequency ω ₁ .

  Thereby, a higher-density and stable plasma discharge is performed in the discharge space, and a high-quality thin film can be formed.

  Here, the frequency of the first power source is preferably 200 kHz or less. The electric field waveform may be a sine wave or a pulse, but is preferably a sine wave. The lower limit is preferably about 1 kHz. Thereby, a higher-density and stable plasma discharge is performed in the discharge space, and a high-quality thin film can be formed.

  On the other hand, the frequency of the second power source is preferably 800 kHz or more. The higher the frequency of the second power source, the higher the plasma density, and a dense and high-quality thin film can be obtained. The upper limit is preferably about 200 MHz. The electric field waveform may be a sine wave or a pulse, but is preferably a sine wave. Thereby, a higher-density and stable plasma discharge is performed in the discharge space, and a high-quality thin film can be formed.

  Although the superposition of sine waves has been described, the present invention is not limited to this, and both pulse waves may be used, one of them may be a sine wave and the other may be a pulse wave. Further, it may have a third voltage component.

Application of a high frequency voltage from such two power sources is necessary to start discharge of a discharge gas having a high discharge start voltage on the first frequency ω ₁ side, and also on the second frequency ω ₂ side. The important point is that it is necessary to increase the plasma density to form a dense and high-quality thin film.

In the thin film deposition apparatus of the present invention, the high-frequency voltage applied between the first electrode and the second electrode is a superposition of the first high-frequency voltage V ₁ and the second high-frequency voltage V ₂ , and discharge When the starting voltage is IV, as described above,
V ₁ ≧ IV> V ₂
Or V ₁ > IV ≧ V ₂
It is preferable to satisfy. More preferably,
V ₁ >IV> V ₂
Is to satisfy. Thereby, a higher-density and stable plasma discharge is performed in the discharge space, and a high-quality thin film can be formed.

  In the present invention, the discharge start voltage refers to the lowest voltage that can cause discharge in the discharge space (electrode configuration and the like) and reaction conditions (gas conditions and the like) used in the actual thin film forming method. The discharge start voltage varies somewhat depending on the type of gas supplied to the discharge space, the dielectric type of the electrode, etc., but may be considered to be substantially the same as the discharge start voltage of the discharge gas alone.

  In the thin film deposition apparatus of the present invention, it is preferable to apply the first high-frequency voltage to the first electrode and apply the second high-frequency voltage to the second electrode. Thereby, a higher-density and stable plasma discharge is performed in the discharge space, and a high-quality thin film can be formed.

  Between the second electrodes 2 ′ a and 2 ′ b and the second high frequency power supply 20, the first high frequency power supply 21 flows so as to flow toward the second electrodes 2 ′ a and 2 ′ b. Two filters 23 are installed and designed to make it difficult for the current from the second power source 20 to pass through and to make the current from the first power source 21 easier to pass through.

  A first filter 22 is installed between the first electrode 5 'and the first high-frequency power source 21 so that the current from the first high-frequency power source 21 flows toward the first electrode 5'. It is designed to make it difficult to pass current from the first power source 21 and to easily pass current from the second power source 20.

  In the present invention, the first filter 22 and the second filter 23 having such properties can be used without limitation. For example, as the first filter 22, a capacitor of several tens to several tens of thousands pF or a coil of about several μH can be used according to the frequency of the second power source. The second filter 23 can be used as a filter by using a coil of 10 μH or more according to the frequency of the first power source and grounding the coil through these coils or capacitors.

  In the thin film deposition apparatus of the present invention, the first electrode, the first high-frequency power source or any of them is provided with a first filter, and the second electrode, the second high-frequency power source or any of them is provided. Preferably, a second filter is connected to the first filter. The first filter makes it difficult for current of a frequency from the first power source to pass through, makes it easier to pass current of a frequency from the second power source, On the contrary, the two filters use a filter that has a function for making it difficult to pass the current of the frequency from the second power source and to easily pass the current of the frequency from the first power source. It is preferable to do this. Here, being difficult to pass means that it preferably passes only 20% or less of the current, more preferably 10% or less. On the contrary, being easy to pass means preferably passing 80% or more of the current, more preferably 90% or more.

  Reference numerals 24a and 24b are high-frequency probes, and reference numerals 25a and 25b are oscilloscopes. The high frequency probes 24a and 24b and the oscilloscopes 25a and 25b are for measuring the applied voltage and the discharge start voltage of the second high frequency power source 20 and the first high frequency power source 21.

  The high frequency voltage (applied voltage) and the discharge start voltage can be measured by the following method.

Measuring method of high-frequency voltages V ₁ and V ₂ (unit: kV / mm):
A high-frequency probe (P6015A) for each electrode part is installed, and the high-frequency probe is connected to an oscilloscope (Tektronix, TDS3012B) to measure the voltage.

Measuring method of discharge start voltage IV (unit: kV / mm):
A discharge gas is supplied between the electrodes, the voltage between the electrodes is increased, and a voltage at which discharge starts is defined as a discharge start voltage IV. The measuring instrument is the same as the above high-frequency voltage measurement.

When air (nitrogen; about 80% by volume, oxygen: about 20% by volume) is used as the discharge gas by the above measurement, the discharge start voltage IV is about 3.4 kV / mm. Therefore, in the above relationship, By applying the first high-frequency voltage as V ₁ ≧ 3.4 kV / mm, the plasma discharge state can be maintained in the discharge space with higher density and stability.

  What is important here is that such a high-frequency voltage is applied to each of the opposing electrodes, that is, applied to the same discharge space from both.

Reference numeral 26 denotes a ground. In addition, the discharge output of the voltage introduced between the electrodes (discharge space) is preferably 1 W / cm ² or more in the same manner for forming a high-quality film, and more preferably 1 to 50 W / cm ² . . Thereby, even with the discharge gas used in the present invention, a higher-density and stable plasma discharge is performed in the discharge space, and a high-quality thin film can be formed.

  In FIG. 4, 10 is a gas introduction part. The gas introduction part 10 has a discharge gas passage 11 for introducing a discharge gas for forming a thin film at the center thereof. The discharge gas passage 11 is discharge gas introduction means according to the present invention. Moreover, the gas introduction part 10 has reactive gas passages 12a and 12b for introducing a reactive gas. The reactive gas passages 12a and 12b are reactive gas introduction means according to the present invention. The discharge gas passage 11 and the reactive gas passages 12a and 12b are separated by gas passage walls 14a and 14b, and the reactive gas passages 12a and 12b are separated from the outside by the gas passage walls 15a and 15b.

  As in the case of FIG. 1, it is preferable to have temperature control means 13a and 13b for controlling the temperature of the discharge gas passage walls 14a and 14b in order to heat the discharge gas.

  Although not shown, the heat insulation control systems 13a and 13b include a temperature sensor unit, a heating unit, and a control unit. Based on the temperature detected by the temperature sensor, heating incorporated in the gas passage wall so as to obtain a desired temperature. The temperature can be raised by the part.

  Thereby, the temperature of the internal piping parts (reactive gas passage walls 14a and 14b) for supplying the discharge gas is controlled so that the temperature of the mixed gas in the discharge space can be set to the temperature of 300 ° C to 3000 ° C. It is preferable to control the temperature at the time of supply of gas to the discharge space to a temperature of 300 ° C to 3000 ° C.

  In addition, the reactive gas is preferably maintained below the thermal decomposition temperature of the thin film forming gas. For this reason, although not shown in the figure, in the reactive gas passage, a separate heat retention control is performed in order to prevent the thin film forming gas component from exceeding the thermal decomposition temperature and to prevent condensation of the thin film forming component. A system is preferably provided.

  The material of the passage walls 14a, 14b, 15a, 15b constituting the discharge gas passage 11 or the reactive gas passages 12a, 12b is a material having corrosion resistance and strength against each gas and high thermal conductivity. If so, the material is not particularly limited, but ceramic is preferable.

  Hereinafter, the discharge gas and the reactive gas will be described.

  The reactive gas is a gas containing a thin film forming gas (raw material gas) containing an element that is a raw material of the thin film, and the thin film forming gas is as described above.

  On the other hand, the discharge gas is a gas containing an inert gas which is a gas necessary for discharging, and does not contain a thin film forming gas.

  In the above-described method in which the first high-frequency electric field and the second high-frequency electric field are superimposed and discharged, it is preferable that the discharge gas mainly contains an inexpensive nitrogen gas, thereby reducing the cost in forming a thin film. Can be planned.

  More preferably, the discharge gas is a gas containing 75 to 100% by volume of nitrogen gas. It is also preferable to use air as the discharge gas. Thereby, cost can be further reduced.

  Further, the discharge gas may contain the inert gas, and examples of the inert gas include helium, neon, argon, krypton, xenon, and radon, which are Group 18 elements of the periodic table.

  The discharge gas may contain the reaction promoting gas described above according to the type of the raw material gas contained in the reactive gas.

  The discharge gas according to the present invention preferably has a dew point of −40 ° C. or lower. By using such a discharge gas, even with the discharge gas used in the present invention, a higher-density and stable plasma discharge is performed in the discharge space, and a high-quality thin film can be formed.

  The reactive gas is preferably supplied to the discharge space at 0.01 to 50% by volume with respect to the discharge gas.

  Next, a thin film deposition method using the thin film deposition apparatus shown in FIG. 4 will be described.

  The substrate 1 is transported to the discharge space between the second electrodes 2'a, 2'b and the first electrode 5 'by a transporting means such as a belt conveyor (not shown). The base material 1 can be repeatedly moved in the direction of the arrow in the discharge space by a belt conveyor.

  On the other hand, a discharge gas is introduced into the discharge gas passage 11 and a reactive gas is introduced into the reactive gas passages 12a and 12b. At this time, the gas passage walls 14a and 14b are heated by the heat retention control systems 13a and 13b as necessary, and the discharge gas is heated. The temperature of the discharge gas is heated to 300 ° C. to 3000 ° C. so that the temperature of the mixed gas in the discharge space can be in the range of 300 ° C. to 3000 ° C. when mixed with the reactive gas. preferable.

  The temperature of the reactive gas is preferably higher than the temperature at which the concentration of the reactive gas is saturated vapor pressure, but is preferably lower than the thermal decomposition temperature of the film-forming gas in the reactive gas. Each gas is introduced between the second electrodes 2'a, 2'b and the first electrode 5 ', that is, into the discharge space, and the second electrodes 2'a, 2'b and the second electrode are under a pressure near atmospheric pressure. A high frequency voltage is applied between the electrodes 5 ′ by the high frequency power sources 20 and 21, and a thin film forming gas (raw material gas) is activated by discharge. Using the activated high-temperature thin film forming gas, the thin film is formed on the base material 1 that has been transported by the belt conveyor. The substrate 1 is repeatedly moved by a belt conveyor to form a thin film uniformly. The substrate 1 after the thin film formation is transported to the outside between the second electrodes 2'a, 2'b and the second electrode 5 'by a belt conveyor.

  In the thin film deposition apparatus of the present invention, it is preferable that the time required for the reactive gas and the discharge gas to pass through the discharge space is 0.5 sec or less. This means that the reactive gas introduced into the discharge space and the time that is present in the discharge space from when the discharge gas is introduced to when the discharge gas is discharged are set to a very short time of within 0.5 sec. (Corresponding to the number of substitutions of 2 times / sec or more). As a result, it is possible to further suppress the situation in which the source gas activated without contributing to the formation of the thin film adheres to the electrode and contaminates the electrode. In the thin film deposition apparatus of the present invention, the time for the reactive gas and the discharge gas to pass through the discharge space is more preferably within 0.2 sec, and particularly preferably within 0.1 sec. As a result, electrode contamination can be particularly suppressed.

Assuming that the time during which the reactive gas and the discharge gas pass through the discharge space is T, T is, for example, the volume v (cm ³ ) of the discharge space and the flow rate v ₁ (cm 2) of the reactive gas supplied into the discharge space. ³ / sec), and the discharge gas flow rate v ₂ (cm ³ / sec), it can be obtained from the following equation.

T (sec) = v / (v ₁ + v ₂ )
At this time, v, v ₁ , v ₂ may be adjusted so that T is 0.5 sec or less.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

Example 1
The treatment was carried out using the roll electrode type discharge treatment apparatus shown in FIG. 3 in which a plurality of electrode systems shown in FIG. Further, here, as shown in FIG. 1, a heated discharge gas is supplied from the discharge gas passage 11, and a reactive gas including a thin film forming gas is supplied from the reactive gas passages 12a and 12b at a predetermined temperature. Here, a high frequency power supply CF-5000-27M (27.12 MHz) manufactured by Pearl Industry was used as the high frequency power supply.

  An ITO thin film was formed on a polyethylene terephthalate base (thickness 180 μm) supplied from a base roll under the following conditions.

<ITO film formation conditions>
(1) Discharge gas
Inert gas: Argon
Reaction-promoting gas: Hydrogen gas (3% relative to noble gas)
(2) Reactive gas
Inert gas: Argon
Thin film forming gas:
Thin film raw material 1 (In (DMHD) ₃ ) 1.0% by volume
DMHD; 3,4-dimethyl-2,5-hexaneone
(Mixed in argon gas with a Lintec vaporizer)
Thin film raw material 2 (tetrabutyltin) 0.05% by volume
High frequency power output density: 10 W / cm ²
Processing speed: 10m / min
The reactive gas including the thin film forming gas was adjusted to 150 ° C. while a heating device was provided in the flow path of the supply gas and the gas temperature was monitored.

  The temperature of the roll electrode which conveys a base material was 50 degreeC, and was maintained at -25 degreeC rather than the glass transition temperature (Tg = 75 degreeC) of a polyethylene terephthalate.

Incidentally, the thermal decomposition temperature of In (DMHD) ₃ as a thin film raw material was about 260 ° C. The thermal decomposition temperature was measured by DSC.

  Further, the temperature of the discharge gas was changed as shown in Table 1 by the heat retention control systems 13a and 13b as temperature control means provided in the discharge gas passage 11 in FIG.

  The film thickness was adjusted to about 100 nm, and the surface specific resistance at that time was determined by the 4-terminal method according to JIS-R-1637. In addition, Mitsubishi Kasei Lorester GP, MCP-T600 was used for the measurement.

  The results are shown in Table 1 for each thin film formed by changing the discharge gas temperature.

  The temperature of the mixed gas in the discharge space is shown in the table.

Example 2
Using the same apparatus as in Example 1, however, as shown in FIG. 4, a low frequency power source of 80 kHz made by Applied Electric is connected to the roll electrode side so that two frequencies can be superimposed and discharged, and the opposite rod electrode side is connected. A 27.12 MHz power source manufactured by Pearl Industry was connected to supply power.
Here, in order to suppress interference of each power, a high frequency filter for grounding the 27.12 MHz high frequency power is installed between the 80 kHz power source and the roll electrode, and between the 27.12 MHz power source and the rod electrode. A low frequency filter for grounding 80 kHz low frequency power was installed.

Under the following conditions, a TiO ₂ thin film was formed on a polyethylene terephthalate base (thickness: 180 μm) supplied from a base roll.

<TiO ₂ deposition conditions>
(1) Discharge gas
Nitrogen gas
Reaction promoting gas: Hydrogen gas (3% of nitrogen gas)
(2) Reactive gas
Nitrogen gas
Thin film forming gas:
Thin film raw material (TTIP) 1.0 vol%
TTIP; Titanium Tetraisopropoxide
(Mixed in argon gas with a Lintec vaporizer)
Output density: 80 kHz power supply 8 W / cm ²
27.12MHz power supply 8W / cm ²
Processing speed: 10m / min
A heating power source is provided in each supply gas flow path, and while monitoring the gas temperature, the reactive gas is changed to 200 ° C., and the temperature of the discharge gas is changed as shown in Table 2 below. The crystallinity of the obtained TiO ₂ thin film was measured using an X-ray diffractometer (X-ray diffraction spectrum for Cu-Kα ray was measured by RINT-TTR2 manufactured by Rigaku Corporation). Note that the thickness of each TiO ₂ thin film to be formed was adjusted to about 100 nm.

  Moreover, the temperature of the roll electrode which conveys a base material was 60 degreeC, and was maintained at -10 degreeC rather than the glass transition temperature (Tg = 75 degreeC) of a polyethylene terephthalate.

Incidentally, the thermal decomposition temperature of TTIP as a thin film raw material was about 280 ° C. (measured by DSC).
The temperature of the mixed gas in the discharge space is shown in the table.

When the temperature of the discharge gas is changed and the mixed gas temperature in the discharge space is within the range of the present invention, crystallinity appears in the TiO ₂ thin film, and it can be seen that the crystal form obtained varies depending on the temperature.
For example, when the discharge gas temperature is 420 ° C. and the mixed gas temperature is 410 ° C., anatase TiO ₂ useful as a photocatalyst appears.

Example 3
Using the same apparatus as in Example 2, a silica film was similarly formed on a polyethylene terephthalate film under the following conditions.

<SiO ₂ film formation conditions>
(1) Discharge gas
Nitrogen gas
Reaction promoting gas: Oxygen gas (5% of nitrogen gas)
(2) Reactive gas
Nitrogen gas
Thin film forming gas:
Thin film material (TEOS) 1.0 vol%
TEOS; tetraethoxysilane
(Mixed in argon gas with a Lintec vaporizer)
Output density: 80 kHz power supply 8 W / cm ²
27.12MHz power supply 8W / cm ²
Processing speed: 10m / min
A heating apparatus was provided during the flow of the supply gas, and while monitoring the gas temperature, the film formation gas was changed to 150 ° C. and the discharge gas temperature was changed as shown in Table 3 to form a film.

  The temperature of the roll electrode was 50 ° C. and was maintained at −25 ° C. above the glass transition temperature of polyethylene terephthalate (Tg = 75 ° C.).

  Incidentally, the thermal decomposition temperature of TEOS as a thin film raw material was about 230 ° C. (measured by DSC).

The film thickness was adjusted to about 30 nm, and the water vapor transmission rate and oxygen transmission rate of the polyethylene terephthalate film on which the obtained SiO ₂ film was formed were measured using a measuring instrument manufactured by Mocon.

  It can be seen that the silica film formed by the method of the present application forms a dense film having a low water vapor transmission rate and oxygen transmission rate.

It is sectional drawing which shows an example of the gas introduction part and electrode part of the film-forming apparatus used for the thin film formation method of this invention. It is a perspective view which shows an example of the electrode currently fixed by the prism shape which can be used by this invention. It is the schematic which shows an example of the whole structure of the film-forming apparatus used for the thin film formation method of this invention. It is sectional drawing which shows another example of the gas introduction part and electrode part of the film-forming apparatus used for the thin film formation method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2a, 2b Application electrode 2'a, 2'b 2nd electrode 3a, 3b, 7 Metal base material 4a, 4b, 6 Dielectric material 5 Ground electrode 5 '1st electrode 8, 20, 21 High frequency power supply 10 Gas introduction Part 11 Discharge gas passage 12a, 12b Reactive gas passage 13a, 13b Thermal insulation control system 14a, 14b Discharge gas passage wall 15a, 15b Reactive gas passage wall 22 First filter 23 Second filter 24a, 24b High-frequency probe 25a, 25b Oscilloscope 25 Roll Rotating Electrode 30 Plasma Discharge Treatment Device 31 Plasma Discharge Treatment Container 32 Discharge Treatment Unit 36 Square Column Type Fixed Electrode 40 Voltage Application Means 50, 80 Gas Supply Means 51, 81 Gas Generator 52 Air Supply Port 53 Exhaust Port 60, 70 Electrode Temperature control means 64, 67 Guide roll 65, 66 Nip roll 6 , 69 partition plate G 'treated flue gas P liquid feed pump

Claims (5)

A gas containing a discharge gas and a thin film forming gas is supplied to the discharge space under atmospheric pressure or a pressure in the vicinity thereof, the gas is excited by applying a high-frequency electric field to the discharge space, and the gas that excites the substrate In the thin film forming method of forming a thin film on the substrate by exposing to the gas, the discharge gas and the gas containing the thin film forming gas are separately supplied to the discharge space, and in the discharge space The method of forming a thin film, wherein the temperature of the mixed gas containing the discharge gas and the thin film forming gas is 300 ° C. or higher and 3000 ° C. or lower. 2. The thin film forming method according to claim 1, wherein a temperature of a mixed gas containing the discharge gas and the thin film forming gas in the discharge space is 500 ° C. or higher and 1000 ° C. or lower. 3. The thin film forming method according to claim 1, wherein in the discharge space, the temperature of the electrode supporting the base material is within a range of ± 50 ° C. with respect to the glass transition temperature of the base material. The method of forming a thin film according to claim 3, wherein the temperature of the electrode supporting the substrate in the discharge space is in the range of -50 ° C to 0 ° C with respect to the glass transition temperature of the substrate. 5. The temperature of the mixed gas containing the discharge gas and the thin film forming gas in the discharge space is near or above the crystallization temperature of the thin film formed on the substrate. A method for forming a thin film according to 1.

Images