JP2007308752A - Water-repellent thin film, and method for producing water-repellent thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a water-repellent thin film where a water-repellent thin film having high water repellency can be easily deposited even on a base material having a large area, and to provide a water-repellent thin film which can be deposited on a base material with a large area at low cost. <P>SOLUTION: The method for producing a water-repellent thin film deposited on the surface of a base material by a plasma CVD process is characterized in that gas components comprising a hydrocarbon gas and a fluorine-containing compound gas are introduced into a region between at least a pair of electrodes provided for generating plasma by discharge under the pressure near the atmospheric pressure, discharge is caused between a pair of the electrodes, thus plasma is generated, so as to crack the gas components, the cracked product of the gas components is brought into contact with the surface of the base material, and a thin film is deposited on the surface of the base material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water repellent thin film formed on a substrate using a plasma CVD method and a method for producing the water repellent thin film.

  Conventionally, a method of forming a water-repellent thin film on the surface of a base material made of a metal material such as aluminum, a ceramic material such as glass or silicon, or an organic material such as fiber, wood, or synthetic resin is known.

  As a method of forming a water-repellent thin film on the surface of the base material, a water-repellent coating film is formed by applying a water-repellent paint on the base material using a coating means such as brush, spray, roll coater or dipping and drying. A method of forming is known (for example, Patent Document 1 and Non-Patent Document 1).

  In Patent Document 1, a water-repellent thin film is formed by dip-coating a paint comprising a silicone resin solution, a silane coupling agent, and an inorganic filler having a specific particle diameter on a metal substrate, and then drying the paint. A method of forming is disclosed. In addition to the high water repellency of the silicone resin thin film, the water-repellent thin film formed by this method has the effect that the inorganic filler forms irregularities on the surface of the thin film to reduce the contact area between the surface of the thin film and the water droplets. It is described that high water repellency is maintained.

  In addition, Non-Patent Document 1 describes a water-repellent paint containing Teflon (registered trademark) particles. The water-repellent paint is applied to the surface of the substrate by application means such as a brush or a spray. The document describes an example in which a water contact angle of 150 ° C. is achieved by a water repellent thin film formed by applying the paint.

  However, the methods described in Patent Document 1 and Non-Patent Document 1 for forming a water-repellent thin film by coating have a very low adhesion force depending on the type of substrate on which the thin film is formed. Moreover, in order to form a coating film with a uniform thickness on a substrate having a large area, it is necessary to increase the film thickness. And when the film thickness is thick, there is a problem that the adhesion to the substrate is lowered, and the thin film formed at the time of cutting, drilling, bending and the like of the substrate is peeled off.

  As a method for solving the above problem, a method of forming a water-repellent thin film using a chemical vapor deposition (CVD) method is known (for example, Patent Document 2 and Patent Document 3).

  For example, in Patent Document 2, an organosilicon compound gas such as organosilane and a fluorine compound gas are decomposed in a gas phase by plasma, high heat, light, or the like, and the decomposition reaction product is deposited on the surface of a substrate. Describes a method of forming a water-repellent thin film. Patent Document 3 describes a method of forming a water-repellent silicon oxide thin film by depositing a reaction product produced by decomposing an organosilicon compound gas by a low temperature plasma method on a substrate.

  In the techniques of Patent Document 2 and Patent Document 3, an organosilicon compound such as organosilane is used as the water-repellent component of the thin film. Since the organosilicon compound generally has a low vapor pressure, it is a liquid at room temperature at atmospheric pressure. When using the organosilicon compound as a gas component for forming a thin film in the CVD method, it is necessary to vaporize the organosilicon compound. In the case of vaporizing an organosilicon compound having a low vapor pressure, it is necessary to vaporize in a high vacuum atmosphere using a vacuum chamber or the like. In such a case, the CVD apparatus used for forming the water repellent thin film is required to have a performance of maintaining a high vacuum, and there is a problem that an expensive apparatus is required.

  In particular, when a water-repellent thin film is formed on a substrate such as a large-area glass plate or when a water-repellent thin film is continuously formed on a rolled steel material during industrial production, a large vacuum chamber and plasma are formed. There is a problem that a CVD apparatus having a region is required and the production cost becomes very high.

Further, in order to uniformly form a water-repellent thin film on a substrate using a large CVD apparatus, it is necessary to supply a gas component for forming a thin film uniformly and efficiently in the plasma forming region. In this case, when the organosilicon compound is used as the main component of the gas for forming the thin film, the organosilicon compound is condensed on the wall surface of the vacuum chamber, for example, due to the temperature distribution in the apparatus, so that the plasma formation region It was difficult to form a uniform thin film on the surface of the substrate due to the variation in the organosilicon concentration.
Japanese Patent Laid-Open No. 5-222339 JP-A-10-130844 Japanese Patent No. 3720974 NTT AT, homepage (URL: www.keytech.ntt-at.co.jp/environ)

  The present invention is a manufacturing method for forming a water-repellent thin film on the surface of a substrate using a plasma CVD method in view of the conventional problems, and has a high water repellency even on a substrate having a large area. It is an object of the present invention to provide a method for producing a water-repellent thin film capable of easily forming a thin film and a water-repellent thin film that can be formed on a substrate having a large area at a low cost.

  As a result of intensive studies to solve the above problems, the present inventors have found that the problem can be solved by the following means.

  That is, the method for producing a water-repellent thin film of the present invention is a method for producing a water-repellent thin film formed on the surface of a substrate by a plasma CVD method, and includes at least a pair of electrodes provided for generating plasma by discharge. A gas component containing a hydrocarbon gas and a fluorine-containing compound gas is introduced into a region between the electrode pair at a pressure near atmospheric pressure, and the gas component is discharged by generating a plasma by discharging between the electrode pair. It decomposes | disassembles, the decomposition product of the said gas component is made to contact a base material surface, and a thin film is formed in the said base material surface, It is characterized by the above-mentioned.

  The decomposition product of the gas component formed by the plasma CVD method has a function of forming a water-repellent thin film on a substrate and etching the formed thin film. The formed water-repellent thin film contains an aggregate of particles in which a plurality of particles are aggregated. On the other hand, unevenness is formed on the surface of the thin film by the etching. And the water-repellent thin film which shows the outstanding water repellency is formed by the water-repellent action of the said water-repellent thin film, and the effect | action which makes the contact area with the water of the said unevenness | corrugation and particle aggregate small. In the method for producing a water-repellent thin film of the present invention, the water-repellent thin film can be formed without using an organic silicon compound that has been used in the production of a conventional water-repellent thin film. Therefore, the water-repellent thin film can be formed at a pressure in the vicinity of atmospheric pressure without maintaining the extremely high vacuum required by the conventional method for producing a water-repellent thin film using an organosilicon compound. Therefore, since a high vacuum state is not required for thin film formation, a water-repellent thin film can be easily formed even on a substrate having a large area.

  The plasma CVD method in the present invention is proposed in, for example, Japanese Patent Application Laid-Open No. 6-2149, in which plasma is generated by glow discharge under a pressure near atmospheric pressure to form a thin film on a substrate. The method described in JP-A-2002-237480 is a method in which a dielectric is formed on at least one of opposing electrodes, plasma is generated at atmospheric pressure by a DC pulse or the like, and a source gas is blown onto a substrate with a gas pressure. For example, various methods such as a film forming method using a rotating electrode as disclosed in JP-A-9-104985 can be used without limitation.

  The electrode pair for generating plasma used in the plasma CVD method in the present invention is preferably an electrode pair arranged to face each other. When electrode pairs arranged opposite to each other are used, discharge is performed by applying a voltage, plasma is generated in a region between the electrode pairs, gas components are decomposed, and a plasma region is formed. By disposing the base material, the water-repellent thin film can be easily formed on the base material. In the case of a large-area substrate or a long substrate, the water-repellent thin film can be easily formed on the large-area substrate by sequentially transferring the substrate to the plasma region.

  In the production method of the present invention, a gas component containing a hydrocarbon gas and a fluorine-containing compound gas is introduced between the electrode pairs.

  In the gas introduction step for introducing the gas component, a gas component containing a hydrocarbon gas and a fluorine-containing compound gas is at a pressure close to atmospheric pressure between the electrode pair provided for generating plasma. 0.01 to 0.1 MPa, preferably 0.08 to 0.1 MPa. In such a pressure range, pressure adjustment is easy and the device configuration is simplified.

  Examples of the hydrocarbon gas include alkanes such as methane, ethane, propane, and butane, alkenes such as ethylene, propylene, and butene, and alkynes such as acetylene.

  Among these, propylene, methane, propane, acetylene and the like are preferably used because of easy gas handling.

On the other hand, examples of the fluorine gas include fluorinated carbonization such as tetrafluoromethane (CF ₄ ), hexafluoroethane (C ₂ F ₆ ), trifluoromethane (CHF ₃ ), and octafluorocyclobutene (C ₄ F ₈ ). In addition to hydrogen and derivatives thereof, a gas preferably used in plasma etching such as sulfur hexafluoride (SF ₆ ) is preferably used.

In the gas component, helium (He), argon (Ar), xenon (Xe), krypton (Kr), etc. are generally used to generate a stable glow discharge in an atmosphere that does not generate reactive radicals. A rare gas or an inert gas such as nitrogen (N ₂ ). As the inert gas, helium is particularly preferable because it has a long life in a metastable excited state.

  Furthermore, the gas component used in the present invention may contain other components, specifically oxygen, water, nitrogen oxides and the like.

  The content ratio of the hydrocarbon gas and the fluorine-containing compound gas in the gas component is 0.01 to 10 (hydrocarbon gas / fluorine-containing compound gas) in a partial pressure ratio, more preferably 0.02 to 2, particularly 0.05 to It is preferably 0.25. In this range, a thin film having moderate unevenness is formed by moderately generating etching due to the decomposition product of the fluorine-containing compound gas. In addition, when the partial pressure ratio is in the range of 0.02 to 2, particularly 0.05 to 0.25, the density of the aggregates of the fine particles constituting the thin film is increased, and further, the water repellency is increased. .

  Moreover, it is preferable that the ratio of hydrocarbon gas is 0.02-7 mol% with respect to the total amount of the said gas component, and the ratio of fluorine-containing compound gas is 0.02-7 mol%. When the ratio of hydrocarbon gas to fluorine gas is within the above range, particularly high water repellency is exhibited.

  In the manufacturing method of the present invention, plasma is generated by discharging between the electrode pairs. The discharge is generated by applying high frequency power to the electrodes. As the discharge, glow discharge is preferable because continuous and stable film formation is possible. For generation of plasma, a high frequency low LF of 13.56 MHz, a DC pulse, or the like can be used.

  And in the area | region where the said plasma was generated, the water-repellent thin film is formed in the base-material surface by making the said decomposition product decomposed | disassembled by plasma contact the surface of a base material. Further, the thin film can be continuously formed by passing the base material through the region at a predetermined speed to bring the decomposition product into contact with the surface of the base material. Thus, by passing the base material through the region between the electrode pair at a predetermined speed, a uniform film thickness can be obtained on a large area base material or a continuous long base material such as a roll-shaped steel plate. A water repellent thin film can be formed.

  The transfer speed is not particularly limited, but the film thickness can be adjusted or migration can be suppressed by adjusting the transfer speed. As a result, it is possible to control the formation density of fine particle aggregates and the network structure.

  In addition, as a base material in this invention, the base material of all forms, such as plate shape which consists of metals, such as aluminum, nickel, copper, ceramics, such as glass and silicon | silicone, organic materials, such as a timber and a synthetic resin, and fibrous form, etc. Can be used. In particular, the production method of the present invention can be applied to a large area base material such as a large area base material or a roll-shaped steel material.

  Moreover, it is preferable that the temperature of the said base material in the thin film formation process in this invention is maintained at 70-350 degreeC, 70-200 degreeC, especially 70-150 degreeC. Maintaining the temperature of the substrate in such a range is preferable from the viewpoint of improving the adhesion of the thin film to the substrate and reducing the thermal deterioration of the substrate.

  In addition, as an electrode pair arrange | positioned mutually facing, it is preferable that the at least one electrode is a rotating electrode. When a rotating electrode is used, arc discharge is difficult to occur because there is no electric field concentration, and the gas flow is uniform in the width direction along the rotating electrode. Can be formed.

  Here, an example of a method for forming a water-repellent thin film on a substrate using a plasma CVD apparatus provided with a rotating electrode will be described more specifically.

  As an example of the configuration of a plasma CVD apparatus provided with a rotating electrode, an electrode pair facing the inside of the chamber as shown in FIG. 1 is provided, and one electrode of the electrode pair is a rotating electrode and the other is a planar electrode. Is mentioned. Here, the rotating electrode functions as a discharge electrode.

  First, the base material 7 is disposed on the planar electrode 6. Then, a gas component is introduced into the chamber 1, and the pressure in the gap (hereinafter referred to as “narrow gap”) between the rotating electrode 9 and the base material 7 is maintained at 0.01 to 0.1 MPa near atmospheric pressure. Then, the plasma is discharged between the electrode pairs to generate line-shaped plasma in a narrow gap. Then, the base material 7 is passed at a predetermined speed so as to cross the plasma space.

  As the rotating electrode, in addition to the cylindrical rotating electrode as shown in the configuration example of the plasma CVD apparatus shown in FIG. 1, an endless belt electrode as shown in FIG. 2 can be used. .

  Moreover, the surface shape of the rotating electrode is not particularly limited, and an uneven shape may be formed on the surface other than the smooth surface. The uneven shape is used to adjust the distance between the rotating electrode and the substrate at a desired position on the base material. For example, when the uneven shape is formed along the rotation direction, the convex portion on the base material is used. It is possible to preferentially generate plasma only at the portion facing the surface, and to form the water repellent thin film preferentially only at that portion. Accordingly, irregularities can be formed on the surface of the formed water-repellent thin film. When the uneven shape is provided on the rotating electrode, there is an effect of diffusing a gas component which is a laminar flow (viscous flow).

  The interval between the rotating electrode and the substrate placed on the planar electrode (the interval between the narrow gaps) is appropriately adjusted depending on the high-frequency power applied to the rotating electrode, the type of gas component used, the composition ratio, and the like. However, it is usually preferably 0.5 to 5 mm, more preferably about 1 to 3 mm. When the interval is too narrow, it is difficult to stably supply the gas component to the narrow gap. Therefore, since the narrow gap variation in the width direction of the rotating electrode becomes remarkable, uniform film formation becomes difficult. In addition, in order to realize stable plasma generation when the narrow gap is too narrow, a high frequency of 100 MHz or more is required to capture plasma charged particles of electrons and ions, which tends to be disadvantageous in cost. is there.

  On the other hand, when the interval is too wide, the film formation rate tends to decrease due to a decrease in electric field and a decrease in plasma density. Further, problems such as a decrease in film formation speed and contamination in the chamber may occur due to the film formation precursor being discharged from the substrate by the laminar flow generated by the rotation of the rotating electrode.

  The peripheral speed of the rotating electrode is preferably 3000 cm / min or more. When the peripheral speed is less than 3000 cm / min, the film forming speed tends to be low, and preferably 10,000 cm / min or more, but considering the improvement in yield, the film forming speed is less than 100,000 cm / min. More preferably it is. In this case, the lifetime until recombination after ionization of the gas component molecules converted into plasma by glow discharge is short, and the mean free path of electrons is also short, so that the glow discharge can be stably generated in the opposing narrow gap. Needs to capture charged particles of electrons and ions in a narrow gap.

  Therefore, when high frequency power is applied to the rotating electrode, a frequency of 100 KHz or higher can be used, but a high frequency of 10 MHz or higher is particularly preferable. By using high frequency of 10 MHz or higher, for example, 13.56 MHz, which is the most readily available commercial frequency, and frequencies of 70 MHz, 100 MHz, and 150 MHz available as a power source, plasma density can be improved and stable plasma can be generated. become.

  Then, plasma is generated between the electrode pair by the discharge, and a decomposition product is formed by decomposing the hydrocarbon gas and the fluorine-containing compound gas. And the water-repellent thin film is formed by making the said decomposition product contact the said base-material surface.

  Next, the water repellent thin film obtained by the production method of the present invention will be described.

  The water-repellent thin film formed by the production method of the present invention is a hydrocarbon-based thin film containing a group consisting of C-Hx and C-Fx (x is an integer of 1 to 3), and the water-repellent thin film The aggregate of the microparticles is formed on the surface.

The presence of the group consisting of C—Hx can be confirmed by the presence of a peak at 2800 to 3000 cm ^{−1 in} the infrared absorption spectrum of the thin film, and the presence of the group consisting of C—Fx is 1120 to 1180 cm ⁻¹ . This can be confirmed by the presence of a peak. Note that the higher the water repellency of the thin film, the more clearly the two peaks are observed.

Moreover, the aggregate of fine particles exists on the surface of the water-repellent thin film of the present invention. Preferably as the density of the aggregates of the fine particles is 130 × 10 ⁶ / cm ² or more, also, is preferably 1 × ^{10 10} / cm ² or less. A thin film obtained by the method for producing a water-repellent thin film is formed by growing in the form of particles. The particles aggregate to form an aggregate. Such microparticles and aggregates of microparticles have the effect of forming irregularities on the surface of the thin film and increasing water repellency.

  Further, the particle diameter of the fine particle aggregate is preferably 0.5 to 5 μm from the viewpoint of water repellency. The agglomerates of the fine particles preferably form a network structure formed by connecting particles almost continuously. When such a network structure is formed, the contact area with water can be particularly reduced, and higher water repellency can be obtained.

  The thickness of the water-repellent thin film of the present invention is not particularly limited, but is preferably about 1 to 1000 nm, more preferably about 5 to 100 nm. If the film thickness is too thick, it takes a long time to form the film, which increases the cost and decreases the adhesion to the substrate. If the film is too thin, sufficient adhesion strength cannot be obtained. There is a fear.

  The water repellent thin film of the present invention described above can achieve excellent water repellency, specifically, a contact angle with water of 100 to 150 degrees or more. Accordingly, a substrate on which such a water-repellent thin film is formed is preferably used for applications such as air conditioner fin materials, metal substrates having antifouling functions, glass substrates for automobiles, mirrors, and the like.

  Below, the manufacturing method of the water-repellent thin film of the present invention will be described in detail by taking as an example a film forming method using a plasma CVD film forming apparatus provided with a rotating electrode in a chamber. In addition to the following method, the present invention can naturally be implemented by, for example, a film forming method using a plasma CVD film forming apparatus using a rotating electrode having no chamber.

  FIG. 1 is a schematic explanatory view showing a configuration example of a CVD film forming apparatus suitably used in the method for producing a water-repellent thin film of the present invention, in which 1 is a film forming chamber, and 2a is a load lock chamber for introducing a substrate. 2b is a load lock chamber for carrying out the substrate, 3a to 3d are gate valves, 4a to 4d are gas inlets, 5a to 5c are leak ports, 6 is a substrate holder, 7 is a substrate, 8 is a bearing, 9 is Rotating electrode, 10 is a base, 11a to 11c are rotating electrode supporting insulators, 12 is a synthetic quartz glass, 13 is a near infrared lamp, 14 is a viewing window, 15 is a radiation thermometer, 16 and 19 are high-frequency power supplies, Reference numeral 20 denotes a matching unit, 18 denotes a heater built in the base material holder, and 21 denotes a glow discharge region (plasma generation region).

  In the apparatus configuration shown in FIG. 1, a substrate introduction load lock chamber 2a and a substrate carry out load lock chamber 2b are connected to the film forming chamber 1 through gate valves 3b and 3c, respectively. A carrier gas such as helium is always introduced into the load lock chambers 2a and 2b from the gas introduction ports 4a and 4b (V1 and V2 are flow rate adjusting valves), and is provided in each of the load lock chambers 2a and 2b. The pressure is adjusted by the leak ports 5a and 5b (V3 and V4 are flow rate adjusting valves), and the load lock chambers 2a and 2b are maintained at a normal pressure (about 0.1 MPa).

  A carrier gas containing an inert gas such as helium as a component is introduced into the film forming chamber 1 through a mass flow (not shown) through a gas inlet 4c. Further, a gas containing a hydrocarbon gas and a fluorine-containing compound gas diluted by bubbling with an inert gas such as helium whose flow rate is adjusted through a mass flow (not shown) is introduced from the gas introduction port 4d. . The pressure in the chamber 1 is adjusted by adjusting the flow rate from the exhaust port 5c.

  A base material 7 is placed on the base material holder 6. The base material holder 6 is first transferred and stored in the load lock chamber 2a with the gate valve 3a opened. Thereafter, the gate valve 3a is closed, the gate valve 3b is opened, and the substrate holder 7 is transferred in the direction of arrow A and stored in the chamber 1, and then the gate valve 3b is closed. It becomes a state.

In the state in which the substrate holder 6 is stored in the chamber 1, a water-repellent thin film is formed on the surface of the substrate 7 placed on the substrate holder 6. After the water repellent thin film is formed on the surface of the base material 7, the gate valve 3c is opened, and the base material holder 7 is stored in the load lock chamber 2b. Subsequently, the gate valve 3c is closed and the gate valve 3d is opened, and the substrate holder 7 and the substrate 7 placed thereon are carried out of the load lock chamber 2b. These series of operations are continuously performed, and the stop and progress of the base material holder 6 can be freely controlled. The rotating electrode 9 is preferably heated by infrared rays emitted from the near-infrared lamp 13 through the synthetic quartz glass 12 and heated to about 150 ° C. The temperature monitor rotating electrode 9 is performed by the radiation thermometer 15 via the observation window 14 made of, for example, BaF _2.

  In the apparatus described above, a water repellent thin film is formed on the substrate 7 by forming plasma by glow discharge 21 in a narrow gap between the rotating electrode 9 and the substrate 7. The principle of forming this water-repellent thin film will be described. The rotating electrode 9 is made of, for example, aluminum, and its size is, for example, a cylindrical shape having a width of about 120 mm and a diameter of about 100 mm, and its edge portion has a curvature of R5 (mm) to prevent electric field concentration. It is rounded with a radius. In addition, the surface of the rotating electrode 9 is coated with a dielectric to prevent arcing. As the dielectric coating at this time, for example, white alumina is formed by thermal spray coating (thickness: about 150 μm).

  The surface of the rotating electrode 9 that forms a narrow gap with the base material 7 has a polishing specification, and an uneven shape is formed as necessary. The rotating electrode 9 is supported by the bearing 8 and the gantry 10. One shaft end of the rotating electrode 9 is a magnet coupling, which is coupled with a magnet (not shown) at the motor end disposed outside the film forming chamber 1 so that the rotating electrode 9 is rotated at 0 to 3000 rpm. Can be rotated in range.

  The gantry 10 is made of, for example, stainless steel, and high frequency power from a high frequency power source 16 can be applied to the gantry 10 via a matching unit 17. When the scanning tip of the substrate holder 6 arrives directly under the rotating electrode 9, the high-frequency power is applied. First, the rotating electrode 9 and the substrate holder 6 (that is, the substrate holder 6 corresponds to the counter electrode). Glow discharge starts in the narrow gap. Next, after the base material holder 6 is sequentially scanned and the base material 7 placed on the base material holder 6 arrives immediately below the rotary electrode 9, the narrow gap is between the rotary electrode 9 and the base material 7. .

  A heater 18 is embedded in the base material holder 6, and the heater 18 is configured so that the temperature of the base material holder 6 can be heated from room temperature to about 300 ° C. The surface of the substrate holder 6 is thermally sprayed with white alumina having a thickness of about 100 μm. Basically, it may be electrically grounded, but as shown in FIG. The high frequency power from the high frequency power supply 19 may be applied via the matching unit 20. In this way, by applying the high frequency power to the substrate holder 6, an increase in plasma density, a plasma containment effect, and the like are exhibited. About the time to apply the power from the high frequency power source 19 to the substrate holder 6, the high frequency power may be applied immediately after the power from the high frequency power source 16 is applied to the rotating electrode 9.

  The matching unit 17 performs frequency tuning and impedance adjustment to match the high frequency power source 16 side and the load side including the matching unit 17, and maximizes power consumption in the entire load circuit including the matching unit 17. And protecting the high-frequency power supply 16 and the high-frequency oscillation circuit (the relationship between the matching unit 20 and the high-frequency power supply 19 is the same).

  FIG. 2 is a schematic explanatory view showing another example of a CVD film forming apparatus for carrying out the present invention. The basic structure is similar to the apparatus structure shown in FIG. Duplicate description is avoided by assigning the same reference numerals. In FIG. 2, although not shown in the drawing for convenience of explanation, in this apparatus as well as the apparatus shown in FIG. 1, the substrate introduction load lock chamber 2a, the substrate carry-out load lock chamber 2b, and the accompanying lock chamber 2b. The member to be arranged is arranged.

  In the apparatus configuration shown in FIG. 2, an endless belt electrode 22 is provided instead of the cylindrical rotating electrode 9, and the endless belt electrode 22 is made of a conductive member made of, for example, thin steel. It is configured to run around two rollers 23 and 24.

  Each of the rollers 23 and 24 has a cylindrical outer peripheral surface, and in the plasma generation region P, the surface of the endless belt electrode 22 and the surface of the substrate 7 extending horizontally are parallel to each other, and the narrow gap distance between them is constant. It is arranged to become. The endless belt electrode 22 travels in the same direction as the movement direction of the base material 7 in the plasma generation region P.

  Of the two rollers 23 and 24, the one located on the right side in FIG. 2 is a metallic drive / feed roller 24. The roller 24 is configured to rotate by rotating the roller 24 with a belt driving motor (not shown). In the film forming chamber 1, the base material 7 placed on the base material holder 6 is moved in the horizontal direction (arrow B direction) by the base material transfer mechanism 25.

  In the plasma CVD film forming apparatus shown in FIG. 2, a gas component is introduced into the film forming chamber 1 from the gas introduction port 4e, and exhausted through the exhaust duct 5e, whereby the film forming chamber 1 has a predetermined atmospheric pressure. To maintain. Then, the endless belt electrode 22 is caused to travel by the rollers 23 and 24, and a relatively wide line-shaped plasma is generated by glow discharge in a narrow gap between the belt electrode 22 and the base material 7, and the base material 7 is moved. A water-repellent thin film is formed on the base material 7 by a chemical reaction of gas.

  FIG. 3 is a schematic explanatory view showing another example of a CVD film forming apparatus using a rotating electrode for carrying out the present invention. In this example, productivity is improved by omitting the gas evacuation / replacement step, and the substrate can be directly inserted and removed from the atmosphere in order to avoid the use of an expensive vacuum vessel. The basic structure of the rotating electrode portion is the same as that in FIG. 1, and the description of the same portion is omitted.

  In this apparatus, the base material 7 is transferred in one direction by the belt conveyor 26. The substrate 7 is placed on one end of the belt conveyor at regular intervals by a substrate handling robot (not shown). Thereafter, the base material 7 is guided into the reaction container as the belt conveyor moves.

  In this apparatus, the entrance (exit) is limited to the opening necessary for the transfer of the substrate 7 to be processed, and the air curtain 27 is provided to block outside air by using the gas flow. ing. The reaction space is filled with an inert gas, and a gas component containing separately introduced hydrocarbon gas and fluorine-containing compound gas is guided to the plasma space by the rotation of the rotating electrode 9, and the water-repellent thin film is formed on the substrate 7. Form.

  FIG. 4 is a schematic explanatory view showing still another example of a CVD film forming apparatus using a rotating electrode for carrying out the present invention.

  In this apparatus, the substrate 7 is coiled, the substrate 7 to be treated is fed from the feed roll 29, and the substrate 7 is wound up by the winding roll 30. The reaction vessel is separated from the outside air by a gas blocking roll 31 installed at the entrance / exit. With such a configuration, the base material 7 can be continuously processed, and the productivity can be remarkably improved.

  Next, the working effects of the present invention will be described more specifically by way of examples. However, the following examples are not of a nature that limits the present invention, and any modifications may be made without departing from the spirit of the preceding and following descriptions. Are also included in the technical scope of the present invention.

Example 1
A water-repellent thin film was formed using the rotating electrode type CVD film forming apparatus shown in FIG.

  In FIG. 1, a substrate holder 6 having a width of 170 mm and a length (length in the transfer direction): 170 mm is used, and a substrate 7 is placed on the substrate holder 6 and placed in the chamber 1. Stowed.

  As the base material 7, an aluminum base material having a width of 100 mm, a length (length in the transfer direction): 150 mm, and a thickness of 90 μm was used.

  And after the front-end | tip of the base-material holder 6 reached right under the rotating electrode 9, the high frequency electric power (frequency: 13.56 MHz, 700W) was applied to the rotating electrode 9 from the high frequency power supply 16. FIG. The substrate holder 6 was connected to ground.

  At this time, the set temperature of the substrate holder 6 was set to 100 ° C., the set temperature of the rotary electrode 9 was set to 100 ° C., and the set temperature of the film forming chamber 1 and its members was set to 100 ° C.

  The rotational speed of the rotating electrode 9 was 1500 rpm (circumferential speed: 45000 cm / min), and the narrow gap between the rotating electrode 9 and the substrate 7 was set to 1 mm. Since the transfer speed of the base material 7 was 10 mm / sec at this time, the discharge time between the ends in the transfer direction of the base material 7 was about 15 seconds.

The pressure in the film forming chamber 1 was controlled by an auto pressure control (not shown) installed in the exhaust port 5c and adjusted to a total pressure of 101 KPa. A gas mixture of helium gas, propylene, and tetrafluoromethane (CF ₄ ) was introduced into the film forming chamber 1. The partial pressure of each gas component was adjusted by adjusting the flow rate of each gas component.

  The total partial pressure of propylene and tetrafluoromethane is fixed at 1.33 KPa (1.33 / 101: 1.3 (mol%) in terms of partial pressure ratio), and the partial pressure ratio of propylene and tetrafluoromethane is 1/9. It was varied in the range of ~ 9/1.

  As an example of the water-repellent thin film thus obtained, a micrograph (30,000 times magnification) of the water-repellent thin film observed with a scanning electron microscope (SEM) when the partial pressure ratio of propylene and tetrafluoromethane is 5/5 ) Is shown in FIG.

  In the micrograph of FIG. 5, it can be seen that fine particles of about 0.05 to 0.2 μm are aggregated to form aggregates having a particle size of about 0.2 to 1 μm. Note that the shape of the microparticles is not a perfect sphere, but may be an irregular spherical shape or may be partially flat or uneven, but the particle diameter in this case refers to the long diameter portion.

Further, the particle density was calculated from the micrograph by the following method.
(Calculation of particle density)
A grid scale having a 1 μm interval was arranged in the micrograph, and the number of fine particle aggregates per unit area was counted and averaged in a plurality of portions.

  On the other hand, the contact angle of the formed water-repellent thin film with water was evaluated by the following method.

(Measurement of contact angle)
Droplets of distilled water were dropped on the surface of the obtained water-repellent thin film so that the droplet diameter was about 2 mmφ. As an example, FIG. 11 shows the state of a droplet on a water-repellent thin film having a contact angle of about 145 degrees obtained in Example 2. And the static contact angle of the said droplet was measured. The measurement was performed in an atmosphere at 25 ° C. The contact angle meter used for the measurement is CA-X150 type manufactured by Kyowa Interface Science Co., Ltd.

  The results are shown in FIG.

  From FIG. 6, it can be seen that as the partial pressure ratio of tetrafluoromethane increases, the contact angle increases and the water repellency is improved. In particular, when the partial pressure ratio between tetrafluoromethane and propylene was in the vicinity of 9/1 (tetrafluoromethane / propylene), the contact angle was about 140 degrees. It can be seen that the particle density is very high at this partial pressure ratio.

  Moreover, an example of the measurement chart by FT-IR of the obtained water-repellent thin film is shown in FIG.9 and FIG.10.

  FIG. 9 shows a thin film having a contact angle of about 115 degrees when the partial pressure ratio between propylene and tetrafluoromethane is about 9/1. FIG. 10 shows the partial pressure ratio between propylene and tetrafluoromethane near 1/9. Sometimes, it is a chart for a thin film showing a contact angle of about 140 degrees.

In the chart of FIG. 10 for a thin film having a contact angle of about 140 degrees, 1120 to 1180 cm indicating the presence of -C-Fx bonds as compared to a peak near 2800 to 3000 cm ^-1 indicating the presence of -C-Hx bonds. ^It can be seen that the peak near ⁻¹ is very large.

On the other hand, in the chart of FIG. 9 of a thin film having a contact angle of about 115 degrees, 1120 indicating the presence of a —C—Fx bond as compared to a peak near 2800 to 3000 cm ⁻¹ indicating the presence of a —C—Hx bond. It can be seen that the peak around ˜1180 cm ⁻¹ is small.

Therefore, as the water repellency of the thin film increases, the peak near 1120 to 1180 cm ⁻¹ indicating the presence of the bond of —C—Fx as compared to the peak near 2800 to 3000 cm ⁻¹ indicating the presence of the bond of —C—Hx. It turns out that becomes large.

(Comparative Example 1 and Comparative Example 2)
In Comparative Example 1, when only propylene is used as a gas for forming a thin film, only Tetrafluoromethane is used as Comparative Example 2, and the water-repellent thin film is used under the same conditions as in Example 1 except for that. Formed. The results are shown in FIG. Comparative Example 1 is a portion where the partial pressure ratio of tetrafluoromethane in FIG. 6 is 0 kPa, and Comparative Example 2 is a portion where the partial pressure of tetrafluoromethane in FIG. 6 is 1.33 kPa.

  In Comparative Example 1 in which a thin film is formed using only propylene, the contact angle is about 100 degrees, and in Comparative Example 2 in which a thin film is formed using only tetrafluoromethane, the contact angle is about 40 degrees. It did not show sufficient water repellency.

(Example 2)
The partial pressure ratio is fixed to 1/9 (propylene / tetrafluoromethane), the partial pressure of propylene is changed in the range of 0.133 to 0.665 kPa, and the high frequency power is (frequency: 13.56 MHz, 1000 W). A water-repellent thin film was formed in the same manner as in Example 1 except that the contact angle was changed, and the contact angle was evaluated. The results are shown in FIG.

(Example 3)
The partial pressure of propylene was 0.026 to 6.65 kPa, and the partial pressure of tetrafluoromethane was 0.026 to 6.65 kPa (0.026 / 101 to 6.65 / 101: 0.026 to 6 in terms of partial pressure ratio). .6 (mol%)) and the total pressure was 101 kPa. At this time, the set temperature of the substrate holder 6 was set to 100 to 250 ° C., the temperature of the rotating electrode 9 was set to 150 ° C., and the film forming chamber 1 and its members were set to 100 ° C.

  The rotational speed of the rotary electrode 9 was 500-1500 rpm (peripheral speed: 15000-45000 cm / min), and the narrow gap between the rotary electrode 9 and the substrate was set to 1 mm. Since the scanning speed of the base material 7 at this time was 3.3 to 17 mm / second, the discharge time between the ends of the base material 7 in the scanning direction was about 8 to 51 seconds.

  At this time, when the partial pressure ratio was 0.01 to 10, the contact angle was particularly improved as compared with the case of propylene alone.

Example 4
In the case where the partial pressure of tetrafluoromethane in Example 1 was 1.19 kPa, a water repellent thin film was formed in the same manner as in Example 1 except that the transfer rate was 3.3 mm / second. The reason for lowering the transfer speed is to suppress the migration of the decomposed / generated active species. FIG. 8 shows an enlarged photograph of the surface with an electron microscope. As shown in FIG. 8, by suppressing migration, fine particles of about 0.05 to 0.2 μm are aggregated on the surface, and a network structure formed by connecting the aggregates almost continuously is observed. It was. The contact angle of water in the thin film was 160 degrees.

It was confirmed that the water repellency was improved when the above film formation was performed on a silicon substrate, a glass substrate, or the like. Similar results were obtained even when methane, propane or the like was used as the hydrocarbon gas and SF ₆ or the like was used as the fluorine-containing compound gas.

It is a schematic explanatory drawing which shows one structural example of the CVD film-forming apparatus for implementing this invention. It is a schematic explanatory drawing which shows the other structural example of the CVD film-forming apparatus for implementing this invention. It is a schematic explanatory drawing which shows the other structural example of the CVD film-forming apparatus for implementing this invention. It is a schematic explanatory drawing which shows the other structural example of the CVD film-forming apparatus for implementing this invention. 2 is a photograph taken with a scanning electron microscope of the water-repellent thin film obtained in Example 1. FIG. It is a graph which shows the contact angle with respect to the water of the water-repellent thin film formed in Example 1, the comparative example 1, and the comparative example 2, and the particle density of a water-repellent thin film. It is a graph which shows the contact angle with respect to the water of the water-repellent thin film formed in Example 2. 4 is a photograph taken with a scanning electron microscope of the water-repellent thin film obtained in Example 4. FIG. 3 is an FT-IR chart of a water-repellent thin film having a contact angle of about 115 degrees obtained in Example 1. FIG. 2 is an FT-IR chart of a water-repellent thin film having a contact angle with water of about 140 degrees obtained in Example 1. FIG. 2 is an enlarged photograph of the state of droplets on a water-repellent thin film having a contact angle with water of about 145 degrees obtained in Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deposition chamber 2a Load lock chamber for substrate introduction 2b Load lock chamber for substrate removal 3a to 3d Gate valve 4a to 4f Gas introduction port 5a to 5f Leak port 6 Substrate holder 7 Substrate 8 Bearing 9 Rotating electrode 10 Mounting base 11a to 11c Insulator 12 Synthetic quartz glass 13 Near-infrared lamp 14 Viewing window 15 Radiation thermometer 16, 19 High-frequency power source 17, 20 Matching device 18 Heater 21 Glow discharge area 22 Belt electrode 23, 24 Roller 25 Base material transfer mechanism 26 Belt Conveyor 27 Air curtain 28 Counter electrode 29 Sending roll 30 Winding roll 31 Gas shut-off roll

Claims (6)

A method for producing a water-repellent thin film formed on a substrate surface by a plasma CVD method,
A gas component containing a hydrocarbon gas and a fluorine-containing compound gas is introduced into a region between at least one pair of electrode pairs provided for generating plasma by discharge at a pressure near atmospheric pressure, and the electrodes The gas component is decomposed by generating a plasma by discharging between a pair, and the decomposition product of the gas component is brought into contact with the substrate surface to form a thin film on the substrate surface. A method for producing an aqueous thin film.   The method for producing a water-repellent thin film according to claim 1, wherein the thin film is formed by allowing the decomposition product to contact the surface of the base material by passing the base material through a region between the electrode pair.   The method for producing a water-repellent thin film according to claim 1 or 2, wherein the discharge is a glow discharge. A water-repellent thin film formed on a substrate surface by a plasma CVD method,
The water-repellent thin film is a hydrocarbon-based thin film containing a group consisting of C-Hx and C-Fx (x is an integer of 1 to 3), and fine particle aggregates are formed on the surface of the water-repellent thin film. A water-repellent thin film formed on a substrate, characterized in that it is formed. The water-repellent thin film according to claim 4, wherein the aggregate is formed on the surface of the water-repellent thin film in an amount of 130 × 10 ⁶ pieces / cm ² or more.   The water repellent thin film according to claim 4 or 5, wherein the aggregate forms a network structure.