JP2014173150A - Production method of water-repellent thin film, and water-repellent treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a water-repellent thin film having super water-repellent property.SOLUTION: Atmospheric pressure plasma is generated by using mixed gas of Ar and Hby an atmospheric pressure plasma generating apparatus 10. The atmospheric pressure plasma is radiated together with a gas flow in the y-axis direction from an opening of a hole 123. Then, hexamethyldisiloxane is formed mistily by using a mist feeding device 20, and mixed with the atmospheric pressure plasma through a mist feeding pipe 207. Hereby, a water-repellent thin film 60 is deposited on the surface of a substrate 30.

Description

  The present invention relates to a method for producing a water-repellent thin film that forms a water-repellent thin film on the surface of a substrate using atmospheric pressure plasma chemical vapor deposition. The present invention also relates to a water-repellent treatment apparatus that forms a water-repellent thin film on a substrate surface and performs a water-repellent treatment.

  Currently, water repellent treatment is performed by depositing a water repellent thin film on the surface of an object in various fields. For example, automotive lamp covers, solar cells, parabolic antennas, etc. for the purpose of preventing fogging, frosting, snowing, water landing, etc., and flexible substrates for electronic devices for the purpose of corrosion resistance and moisture proofing, Water repellent treatment is applied.

  As a conventional water-repellent treatment method, there is a method of forming a water-repellent thin film in a vacuum such as an evaporation method or a chemical vapor deposition method. However, a method of forming a film in a vacuum by an evaporation method or the like has a problem in terms of mass productivity, simplicity, and cost because a vacuum apparatus is required. A method of applying a water-repellent material by spraying or the like is also known. However, this method also has a drawback that the adhesiveness of the water repellent material is weak.

  As another water repellent treatment method, there is a method described in Patent Document 1. Patent Document 1 describes that a water-repellent thin film made of a carbon-containing silicon compound is formed on a plastic substrate by a plasma CVD (chemical vapor deposition) method using an organic silicon compound as a source gas, and water-repellent treatment is performed. Has been. In addition, it is described that the plastic substrate is cooled to Tg or less during the formation of the water-repellent thin film so that the atmosphere does not contain oxygen. This water repellent treatment method enables continuous treatment at low cost. In addition, a method using atmospheric pressure plasma as plasma in the plasma CVD method is also known. When atmospheric pressure plasma is used, high-speed processing is possible because of high plasma density.

JP 2011-12285 A

  The water repellent treatment method of Patent Document 1 is to obtain water repellency by the surface free energy of the water repellent thin film. However, it is difficult to obtain high water repellency with surface free energy alone, and in particular, it is difficult to obtain super water repellency (when the contact angle of water droplets on the surface is 150 ° or more), and control of water repellency is easy. is not. Further, there has been a demand for a water repellent treatment method capable of high-speed treatment as compared with Patent Document 1.

  Accordingly, an object of the present invention is to provide a method for producing a water-repellent thin film capable of forming a water-repellent thin film on a substrate and obtaining high water repellency, and a water-repellent treatment apparatus. In particular, an object is to realize a water repellent treatment method capable of performing a water repellent treatment on a desired part of a three-dimensional base material.

  The present invention relates to a method for producing a water-repellent thin film on a substrate surface using atmospheric pressure plasma chemical vapor deposition using an organosilicon compound as a raw material for the water-repellent thin film. Using a liquid material, atmospheric pressure plasma is generated using a gas containing an inert gas and not containing an organosilicon compound, and the water-repellent thin film raw material is mixed with atmospheric pressure plasma as a mist. A method for producing a water-repellent thin film, comprising subjecting an aqueous thin film to chemical vapor deposition on the surface of the substrate.

  The water repellency of the water-repellent thin film can be controlled by the distance between the atmospheric pressure plasma and the substrate surface and the position of mist introduction into the atmospheric pressure plasma. In particular, the surface of the water-repellent thin film can be made super water-repellent by introducing the mist in the vicinity of the generating portion of the atmospheric pressure plasma and arranging the substrate so that the surface of the substrate is in the emission region of the atmospheric pressure plasma. it can.

  As a raw material for the water-repellent thin film, a liquid organic silicon compound or a solid or gaseous organic silicon compound dissolved in a solvent can be used. A plurality of types of organosilicon compounds may be mixed and used. As the organosilicon compound, a compound having an alkyl group such as a methyl group or an ethyl group and having a Si—O bond can be used. For example, hexamethyldisiloxane, hexamethyldisilazane, hexamethyldisilane, tetra For example, methyldisiloxane can be used.

  The thickness (average thickness) of the water-repellent thin film is desirably 10 nm or more in order to sufficiently exhibit the water repellency or to sufficiently provide the adhesion and durability of the water-repellent thin film. More desirably, the thickness is 10 to 10,000 nm.

  The water-repellent thin film material is misted by an ultrasonic method that mists by ultrasonic vibration by an ultrasonic vibrator, a pressure method that mists by the principle of spraying, a liquid that drops on a rotating disk, and centrifugal force Various methods such as a rotating disk method, an ink jet method, and the like that are dispersed by mist to form a mist can be used. According to the ultrasonic method, the generated mist has a diameter as small as several μm and has a small initial speed, so that it stays in the air. Therefore, the mist can be conveyed by an inert gas such as Ar and mixed with the atmospheric pressure plasma, and the flow rate, flow rate, supply amount, etc. of the mist can be easily controlled by controlling the inert gas. As a result, the film forming speed and water repellency of the water repellent thin film can be easily controlled.

  The mist may be mixed into the atmospheric pressure plasma from a plurality of directions. Moreover, it is good to spray and mix in the direction perpendicular | vertical with respect to the direction through which atmospheric pressure plasma flows. This is because a more uniform water-repellent thin film can be formed.

  As a gas for generating atmospheric pressure plasma, a rare gas such as helium, neon, or argon, or an inert gas such as nitrogen can be used, and a raw material for a water-repellent thin film such as hydrogen, oxygen, or air is used as the inert gas. A gas in which a gas other than the gas is mixed can be used. In order to stably generate atmospheric pressure plasma, atmospheric pressure plasma may be generated in a container filled with an inert gas such as nitrogen, and a water-repellent thin film may be formed in the container. .

  The substrate can be of any material and shape. It does not need to be flat and may have a three-dimensional shape.

  The present invention also provides a water-repellent treatment that uses the atmospheric pressure plasma chemical vapor deposition using an organosilicon compound as a raw material for the water-repellent thin film to form a water-repellent thin film on the surface of the substrate, thereby repelling the surface of the substrate. In the apparatus, an atmospheric pressure plasma generator for generating atmospheric pressure plasma using a gas containing an inert gas and not containing an organosilicon compound, and using a liquid material as a raw material for the water-repellent thin film, the raw material for the water-repellent thin film And a mist supply device for mixing the mist with atmospheric pressure plasma.

  It is preferable that the distance between the atmospheric pressure plasma and the substrate surface and the position where the mist is introduced into the atmospheric pressure plasma are variable. It is possible to provide a water-repellent treatment apparatus that can easily control the water repellency of the water-repellent thin film.

  According to the present invention, it is possible to easily form a water-repellent thin film having a fine structure on the surface of the substrate, and to easily treat the surface of the substrate to have high water repellency. In the present invention, the water repellency can be easily controlled by the distance between the atmospheric pressure plasma, the substrate surface and the substrate surface, and the position of the mist introduced into the atmospheric pressure plasma. Further, since the mist is mixed after the atmospheric pressure plasma is generated, the generation of the atmospheric pressure plasma is stable, and the generation of the water-repellent thin film is also stable. Further, the present invention can form a water-repellent thin film at high speed at normal temperature and normal pressure, and can reduce the manufacturing cost and perform high-speed processing.

The figure which showed the structure of the water-repellent treatment apparatus. FIG. 3 is a cross-sectional view showing the configuration of the atmospheric pressure plasma generator 10. FIG. 3 is a cross-sectional view showing the configuration of the atmospheric pressure plasma generator 10. The figure which showed the structure of the electrodes 120a and 120b. The figure which showed the relationship between the distance D or the distance L, and water repellency. The graph which showed the FT-IR measurement result of the water-repellent thin film 60. Graph showing the distance D dependent Si-CH ₃ bonds of the peak area ratio Si-O-Si bonds. The SEM image of the surface or cross section of the water-repellent thin film 60. The SEM image of the surface or cross section of the water-repellent thin film 60. The figure which showed the manufacturing process of the water-repellent thin film.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  First, the water repellent treatment apparatus 1 used for manufacturing the water repellent thin film of Example 1 will be described.

  As shown in FIG. 1, the water repellent treatment apparatus 1 includes an atmospheric pressure plasma generation apparatus 10, a mist supply apparatus 20, a stage 40 on which a substrate 30 as an object to be processed is disposed, an atmospheric pressure plasma generation apparatus 10, a substrate. 30 and a stage 50 in which the stage 40 is disposed. Hereinafter, each configuration will be described in detail.

  First, the configuration of the atmospheric pressure plasma generator 10 will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing a configuration of the atmospheric pressure plasma generator 10, and FIG. 3 is a cross-sectional view perpendicular to the longitudinal direction of the plasma region P of the atmospheric pressure plasma generator 10.

As shown in FIG. 2, the atmospheric pressure plasma generator 10 has a housing 100 made of a sintered body made of alumina (Al ₂ O ₃ ) as a raw material. In addition to alumina, a material that is highly resistant to atmospheric pressure plasma generated therein can be used. For example, sintered boron nitride (PBN) can be used.

  Inside the housing 100 is provided a plasma region P that extends linearly in the longitudinal direction (hereinafter, this direction is referred to as the x-axis direction). The casing 100 has a gas inlet 102 including a hole 105 having a diameter of 8 mm, two holes 103 having a diameter of 5 mm, a diffusion plate 104 in which the hole 103 is formed, and a guide portion 106. The hole 103 may have a rectangular shape or a slit shape having long sides in the x-axis direction. The gas inlet 102 is connected to the supply pipe 101, and a gas for generating atmospheric pressure plasma is introduced from the supply pipe 101 to the gas inlet 102.

  As the gas for generating the atmospheric pressure plasma, a rare gas such as helium, neon, or argon or an inert gas such as nitrogen can be used, and a hydrogen repellent thin film such as hydrogen, oxygen, or air is used as the inert gas. A gas mixed with a gas other than the source gas can be used. In particular, when a gas mixed with hydrogen is used, oxidation of electrodes 120a and 120b described later can be suppressed by the reduction action of hydrogen.

  The gas introduced into the gas inlet 102 flows from the hole 105 to the diffusion plate 104, is divided into two in the x-axis direction by the diffusion plate 104, and is guided from the hole 103 toward the plasma region P.

  The guide portion 106 has a diameter 1... For flowing gas in a direction perpendicular to the x-axis direction (hereinafter, a direction in which gas flows in this direction is referred to as a y-axis direction) uniformly in the x-axis direction of the plasma region P. It has a number of holes of 5mm. The guide portion 106 is the upstream side wall surface of the plasma forming region P of the housing 100 in which a large number of holes are formed, and the diffusion portion 108 is configured by the large number of holes and the wall surface. A discharge part 121 is formed on the downstream side wall surface of the plasma generation region P of the housing 100. A large number of holes 123 having an axis in the y-axis direction are arranged in the discharge portion 121 along the x-axis direction. The hole 123 has a diameter of 0.5 mm, and the holes 123 have an interval in the x-axis direction of 2.5 mm, for a total of 16 holes.

  The plasma region P has a rectangular shape with a short side of 2 mm and a long side (parallel to the y-axis direction) of 5 mm, and a length of 2 cm in the x-axis direction.

  Electrodes 120a and 120b are provided at both ends of the plasma region P in the x-axis direction so as to be spaced apart from each other. As shown in FIG. 4, the electrodes 120 a and 120 b are uneven surfaces having a large number of recesses (hollows) H each having a depth of about 0.5 mm. As a material of the electrodes 120a and 120b, stainless steel, molybdenum, tantalum, nickel, copper, tungsten, platinum, or an alloy thereof can be used. As a power source, a commercial AC power source of 100 V and 60 Hz is used, and this is boosted to 9 kV and applied to the electrodes 120a and 120b. Note that the voltage to be applied is not limited to this, and any direct current, alternating current, pulse, or any other value can be used, and the frequency is not limited.

  A gas for generating atmospheric pressure plasma is introduced from the gas inlet 102 at room temperature (1 to 30 ° C.) and normal pressure (atmospheric pressure, but about 0.5 to 2 atm is atmospheric pressure), and the electrode 120a , 120b, atmospheric pressure plasma is generated in the plasma region P. The atmospheric pressure plasma rides on the gas flow and extends in the y-axis direction through the hole 123 to the outside of the housing 100.

  Next, the configuration of the mist supply device 20 will be described. As shown in FIG. 1, the mist supply device 20 includes a T-shaped joint 201, an aluminum film 202 stretched so as to block one opening of the joint 201, and a container 204 that holds water 203. The ultrasonic transducer 205 is disposed in the water 203 and on the bottom surface of the container 204. The opening 201 a of the joint 201 is disposed in the water 203 of the container 204. Further, in a recess surrounded by the aluminum film 202 and the wall surface of the joint 201, hexamethyldisiloxane 206, which is a liquid water-repellent thin film material, is held.

  As a raw material for the water-repellent thin film, a liquid organosilicon compound other than hexamethyldisiloxane 206 can be used, and a solution obtained by dissolving a solid or gaseous organosilicon compound in a solvent can also be used. A plurality of types of organosilicon compounds may be mixed and used. As the organosilicon compound, a compound having an alkyl group such as a methyl group or an ethyl group and having a Si—O bond can be used. For example, hexamethyldisilazane, hexamethyldisilane, tetramethyldisiloxane, etc. Can be used.

  This mist supply device 20 vibrates the aluminum film 202 by vibrating the water 203 by ultrasonic vibration by the ultrasonic vibrator 205, and further vibrates the hexamethyldisiloxane 206 by vibration of the aluminum film 202, thereby producing hexamethyl. Disiloxane 206 is misted. The mist-formed raw material 206 of the water-repellent thin film is mixed and conveyed with Ar which is a carrier gas introduced from one opening 201b of the two openings on the side where the aluminum film 202 of the joint 201 is not stretched, The mist supply pipe 207 connected to the other opening 201c is transported to the vicinity of the atmospheric pressure plasma irradiation unit of the atmospheric pressure plasma generator 10. The axial direction of the mist supply pipe 207 in the vicinity of the mist inlet 207a (the opening on the side where mist is introduced into the atmospheric plasma) is perpendicular to the direction in which the atmospheric plasma flows. When the vicinity of the mist introduction port 207a of the mist supply pipe 207 moves along the flow direction of mist, the position of the mist introduction port 207a is variable along the flow direction of atmospheric pressure plasma. Thereby, it is comprised so that the mist introduction | transduction position to atmospheric pressure plasma can be controlled. The diameter of the mist supply pipe 207 is 6.4 mm. In addition, the supply amount of mist to the atmospheric pressure plasma can be easily controlled by the flow rate, flow rate, etc. of Ar.

  In addition to Ar, a rare gas such as helium, neon, or argon, or an inert gas such as nitrogen can be used as the carrier gas.

  According to the mist supply device 20, since the liquid is misted by the ultrasonic vibrator, it is possible to generate a mist with a droplet diameter of several μm and a small variation in diameter. Further, since the initial velocity of the droplet is small and stays in the space, the flow rate and flow rate of the mist can be easily controlled by Ar as the carrier gas.

  The stage 40 holds the Si substrate 30 that is an object to be processed, and is disposed inside the housing 50. The stage 40 is movable, and a continuous water-repellent treatment can be performed by adjusting the distance between the atmospheric pressure plasma and the Si substrate 30 or by performing processing while moving the Si substrate 30.

  The housing 50 has a supply pipe 501 and an exhaust pipe 502 attached thereto, and nitrogen is introduced into the housing 50 from the supply pipe 501. Thereby, the inside of the housing 50 is filled with nitrogen. Further, the exhaust amount of the gas inside the housing 50 is controlled by the exhaust pipe 502, and the pressure inside the housing 50 is kept constant. Thereby, when atmospheric pressure plasma is generated by the atmospheric pressure plasma generator 10 inside the housing 50, the atmospheric pressure plasma can be stabilized.

  Next, the manufacturing method of the water repellent thin film of Example 1 is demonstrated.

First, the Si substrate 30 which is a to-be-processed object was arrange | positioned on the stage 40 (refer Fig.10 (a)). Next, atmospheric pressure plasma was generated by the atmospheric pressure plasma generator 10 using a mixed gas of Ar and H ₂ (the ratio of H ₂ was 1 vol%). Atmospheric pressure plasma was applied to the gas flow and irradiated from the opening of the hole 123 in the y-axis direction, and the light emitting region extended by 9 mm in the y-axis direction. The flow rate of the mixed gas was 5 slm. Then, using the mist supply device 20, hexamethyldisiloxane was misted and mixed with atmospheric pressure plasma through the mist supply pipe 207. The mist was discharged from the mist inlet 207a of the mist supply pipe 207 in the axial direction of the mist supply pipe 207, that is, in the direction perpendicular to the gas flow direction of the atmospheric pressure plasma, and mixed with the atmospheric pressure plasma. Further, nitrogen was supplied from the casing 501 to the inside of the casing 50 at 5 slm, the amount of gas discharged from the exhaust pipe 502 was adjusted, and the pressure inside the casing 50 was adjusted to a normal pressure. The Si substrate 30 on the stage 40 was set to room temperature without being heated or cooled.

  Thereby, the water-repellent thin film 60 was deposited on the surface of the substrate 30 (see FIG. 10B). In the conventional atmospheric pressure plasma CVD method, gas is used as a raw material of the water-repellent thin film 60, or a solid or liquid material is volatilized into a gas, and the raw material gas is mixed with an inert gas such as Ar, Atmospheric pressure plasma was generated using a mixed gas. On the other hand, in Example 1, atmospheric pressure plasma is generated without mixing the raw material gas of the water-repellent thin film 60 with the inert gas, and a mist-like water-repellent thin film raw material is separately mixed with the atmospheric pressure plasma. As described above, since the atmospheric pressure plasma is generated without mixing the raw material of the water repellent thin film, the atmospheric pressure plasma can be stably generated, and as a result, the water repellent thin film 60 is stably generated. And variations in the thickness and composition of the water repellent thin film 60 can be reduced. In addition, the separation of the generation of atmospheric pressure plasma and the mixing of mist improves the controllability of the water-repellent thin film 60 such as water repellency, film forming speed, and processing area.

  Further, the surface of the water-repellent thin film 60 manufactured by this manufacturing method has a shape having a fine concavo-convex structure 61 having a large number of branch-like branches such as snow crystals. High water repellency can be obtained by the surface free energy by the material of the water repellent thin film 60 and the fine uneven structure 61 on the surface of the water repellent thin film 60.

  The water repellency can be controlled by the distance between the atmospheric pressure plasma and the Si substrate 30 and the introduction position of hexamethyldisiloxane mist. In particular, super water repellency can be obtained by making the Si substrate 30 be in the atmospheric pressure plasma emission region and setting the mist introduction position in the vicinity of the atmospheric pressure plasma generation part (in the vicinity of the plasma region P). In the water repellent treatment apparatus 1 of the first embodiment, the distance D from the plasma irradiation port of the atmospheric pressure plasma generator 10 (the opening of the hole 123 on the Si substrate 30 side) to the surface of the Si substrate 30 in the y-axis direction is Since it can be made variable by movement, the distance between the atmospheric pressure plasma and the Si substrate 30 can be controlled by this. Further, the distance L from the plasma irradiation port (opening on the Si substrate 30 side of the hole 123) of the atmospheric pressure plasma generator 10 to the mist introduction port 207a in the y-axis direction is made variable by moving the mist supply pipe 207. Therefore, the mist introduction position can be controlled. The water repellency can also be controlled by the flow rate and flow rate of the mist introduced into the atmospheric pressure plasma. Similarly, the film forming speed of the water-repellent thin film 60 can be controlled by controlling the distance D and distance L, the flow rate and flow rate of mist, and the like. Further, the processing area can be controlled by the area of the plasma region P.

  The water-repellent thin film 60 is an organic silicon compound including an Si—O bond or an Si—C bond, or an inorganic silicon compound (that is, an Si—O bond and no Si—C bond). The proportion of these bonds in the water-repellent thin film 60 can be controlled by changing the material of the water-repellent thin film 60, adjusting the distance between the atmospheric pressure plasma and the Si substrate 30, or adjusting the mist introduction position. It is.

  The thickness (average thickness) of the water repellent thin film 60 is desirably 10 nm or more. This is because the water repellency is sufficiently exhibited, or the adhesion and durability of the water repellency thin film is sufficient. More desirably, the thickness is 10 to 10,000 nm.

  According to the manufacturing method of the water-repellent thin film 60 of Example 1 described above, the water-repellent treatment of the Si substrate 30 can be performed at normal temperature and normal pressure, so that low cost, high rotation rate, and high-speed treatment are possible. It is. Moreover, since atmospheric pressure plasma is generated without mixing the raw material of the water repellent thin film 60, the water repellent thin film 60 can be generated stably. Moreover, the manufacturing method of the water repellent thin film 60 of Example 1 can control water repellency easily.

[Experimental example]
FIG. 5 is a result of examining the relationship between the distance D from the plasma irradiation port to the surface of the Si substrate 30 and the water repellency of the water-repellent thin film 60 subjected to the water-repellent treatment by the method for producing the water-repellent thin film of Example 1. . The water repellency was evaluated by the contact angle tangent method, and the distance D was changed to 7, 9, 11, and 13 mm. Further, the distance L from the plasma irradiation port to the mist introduction port 207a was 0 mm, that is, mist was introduced into the root portion of the atmospheric pressure plasma.

  First, the contact angle of the Si substrate 30 on which the water repellent thin film 60 was not formed was 36.5 °. On the other hand, when the water-repellent thin film 60 was formed with D = 7 and 9 mm and the water-repellent treatment was performed, the contact angle exceeded 150 ° as shown in FIG. Further, when water repellent treatment was performed with D = 11 mm, the contact angle was 125 °, and when water repellent treatment was performed with D = 13 mm, the contact angle was 117 °, and strong water repellency was obtained. Further, FIG. 5 shows that the water repellency tends to decrease as the distance D increases.

  Further, in order to investigate the relationship between the mist introduction position and the water repellency, the water repellency was evaluated in the same manner as described above even when the distance L was 2 mm and the distance D was 9, 11, and 13 mm. As a result, as shown in FIG. 5, it was found that when the distance L is 2 mm, the water repellency is lower than when the distance L is 0 mm. From this, it is considered that the water repellency decreases as the distance L increases.

FIG. 6 is a graph showing chemical bonds of the water repellent thin film 60 evaluated by FT-IR (Fourier transform infrared spectroscopy). The peak in the vicinity of wave number 1070 cm ⁻¹ is a peak due to Si—O—Si bond, and the peak in the vicinity of wave number 1270 cm ⁻¹ is a peak due to Si—CH ₃ bond. The water repellent thin film 60 was formed by changing the distance D to 7, 9, 11, and 13. The distance L was set to 0 mm. From FIG. 6, it was found that in any case, the water-repellent thin film 60 had a structure having Si—O—Si bonds and Si—CH ₃ bonds.

FIG. 7 shows a result of calculating the peak area ratio of Si—CH ₃ bonds to Si—O—Si bonds in the water-repellent thin film 60 from the measurement results of FIG. It is. From FIG. 7, it was found that when the distance D is 7 mm, the ratio of Si—CH ₃ bonds is lower than when the distance D is 9, 11, and 13 mm. On the other hand, as shown in FIG. 1, when the distance D is 7 mm, super water repellency is obtained. From the result that the water repellency is higher than that in the case of the distance D = 11, 13 mm although the ratio of the hydrophobic Si—CH ₃ bond is lower than that in the case of the distance D = 11, 13 mm, the distance D is The water repellency at 7 mm is not only due to the contribution of surface free energy depending on the chemical bond, but suggests that there are other factors. That is, it is suggested that the fine structure on the surface of the water repellent thin film 60 contributes to water repellency.

  Therefore, the inventors analyzed the surface and cross section of the water-repellent thin film 60 by SEM. FIG. 8 shows the SEM image. The surface and the cross section of the water-repellent thin film 60 were photographed while changing the distance L to 0 mm and the distance D to 7, 9, 11, and 13 mm. As shown in FIG. 8, it was found that a fine uneven structure 61 was formed on the surface of the water repellent thin film 60 as expected. In the fine concavo-convex structure 61, the undulations of the concavo-convex portions become smaller and flatter as the distance D is larger, and the undulations of the concavo-convex portions become more severe as the distance D is smaller. Compared with the results of FIG. 5, it was found that the undulation of the fine concavo-convex structure 61 is large and that many branched structures are the factors that contribute to the high water repellency of the water-repellent thin film 60.

  FIG. 9 is an SEM image obtained by photographing the surface of the water-repellent thin film 60 while changing the distance L to 2 mm and the distance D to 9, 11, and 13 mm. Comparing FIG. 8 and FIG. 9, it was found that as the distance L is increased, the unevenness of the surface of the water repellent thin film 60 is reduced and becomes flat.

  From the above experimental results, it is presumed that the water repellency changes depending on the distance D and the distance L because of the following mechanism.

  When the distance D is small, the surface of the Si substrate 30 is included in the light emission region of the atmospheric pressure plasma, and many dangling bonds are formed on the surface of the Si substrate 30. Since the radicals generated by the atmospheric pressure plasma are bonded to the unbonded hands and are deposited in a branch shape, a fine concavo-convex structure 61 is formed on the surface of the water-repellent thin film 60. Therefore, the contribution of the water repellency improvement by the concavo-convex structure 61 becomes large, and high water repellency is obtained.

  When the distance D is large, the surface of the Si substrate 30 is out of the light emission region of the atmospheric pressure plasma, and dangling bonds on the surface of the Si substrate 30 are reduced. Since radicals generated by atmospheric pressure plasma diffuse on the surface of the Si substrate 30, they are uniformly deposited on the surface of the Si substrate 30, and the surface of the water-repellent thin film 60 becomes flat. Therefore, the water repellency contributes greatly to the surface free energy due to the material of the water repellent thin film 60, and the water repellency is lower than when the distance D is small.

  When the distance L is small, radicals having high reactivity generated by atmospheric pressure plasma are polymerized in the air to form fine particles. Since the fine particles are deposited on the surface of the Si substrate 30, the surface of the water repellent thin film 60 formed by the volume becomes rough, and a fine uneven structure 61 is formed on the surface of the water repellent thin film 60. Therefore, high water repellency can be obtained.

  When the distance L is large, the number of radicals that polymerize in the air decreases, and fine particles are not formed so much. Fine particles deposited on the surface of the Si substrate 30 are also reduced. Therefore, the surface of the water repellent thin film 60 becomes flat. Therefore, the water repellency is lower than when the distance L is small.

  The generation of atmospheric pressure plasma in the method of manufacturing the water-repellent thin film of Example 1 is not limited to the atmospheric pressure plasma generator 10 having the configuration shown in FIGS. An atmospheric pressure plasma generator can be used.

  Moreover, the mist formation of the raw material of the water-repellent thin film 60 is not limited to the ultrasonic vibration as in the first embodiment, and the mist may be formed by other methods. For example, a pressure method, a rotating disk method, an ink jet method, or the like can be used.

  In Example 1, a Si substrate is used as an object to be processed, but the present invention can form a water-repellent thin film on various materials other than Si base. For example, a plastic material such as PET (polyethylene terephthalate) can be used as the object to be processed. Further, in Example 1, the flat Si substrate 30 is used as the object to be processed, but the present invention is not limited to the flat base material, and part or all of various three-dimensional shapes. This region can be subjected to water repellent treatment.

  In the first embodiment, the water repellent treatment is performed inside the housing 50 in order to stably generate the atmospheric pressure plasma. However, the water repellent treatment is performed in a normal atmosphere without the housing 50. You may make it perform.

  In the first embodiment, the mist is mixed with the atmospheric pressure plasma from only one place, but may be mixed from a plurality of places. In the first embodiment, the mist is sprayed in a direction perpendicular to the flowing direction of the atmospheric pressure plasma and mixed with the atmospheric pressure plasma, but it is not always necessary to mix in such a direction. However, when the mist is mixed in the direction as in the first embodiment, the water repellent thin film 60 can be made more uniform.

  The present invention is particularly effective when a water repellent treatment is applied to a part of a three-dimensional base material. For example, water repellent treatment can be performed only on the drinking mouth portion of the beverage plastic bottle container.

DESCRIPTION OF SYMBOLS 1: Water repellent processing apparatus 10: Atmospheric pressure plasma generator 20: Mist supply apparatus 30: Substrate 40: Stage 50, 100: Case 60: Water-repellent thin film 61: Fine uneven structure 101: Supply pipe 102: Gas introduction port 103, 105, 123: Hole 106: Guide part 108: Diffusion part 120a, b: Electrode 121: Discharge part 201: Joint 202: Aluminum film 203: Water 204: Container 205: Ultrasonic vibrator 206: Hexamethyldisiloxane 207 : Mist supply pipe P: Plasmaization region H: Hollow

Claims (11)

In the method for producing a water-repellent thin film, the water-repellent thin film is formed on the substrate surface using atmospheric pressure plasma chemical vapor deposition using an organosilicon compound as a raw material for the water-repellent thin film
Using a liquid material as a raw material for the water-repellent thin film,
An atmospheric pressure plasma is generated using a gas containing an inert gas and not containing an organosilicon compound;
The water-repellent thin film is mixed with the atmospheric pressure plasma as a mist, and the water-repellent thin film is grown on the substrate surface by chemical vapor deposition.
A method for producing a water-repellent thin film.   The water repellency of the water repellent thin film is controlled by a distance between the atmospheric pressure plasma and the substrate surface, and a position where the mist is introduced into the atmospheric pressure plasma. A method for producing an aqueous thin film.   The surface of the water-repellent thin film is made super-water-repellent by supplying the mist to the vicinity of the generating portion of the atmospheric pressure plasma and disposing the substrate so that the surface of the substrate is in the emission region of the atmospheric pressure plasma. The method for producing a water-repellent thin film according to claim 1.   The method for producing a water-repellent thin film according to any one of claims 1 to 3, wherein the raw material for the water-repellent thin film is made mist by ultrasonic vibration.   The method for producing a water-repellent thin film according to any one of claims 1 to 4, wherein the mist is discharged and mixed in a direction perpendicular to a direction in which the atmospheric pressure plasma flows. .   The method for producing a water-repellent thin film according to any one of claims 1 to 5, wherein the gas for generating atmospheric pressure plasma is a mixed gas of argon and hydrogen.   The method for producing a water-repellent thin film according to any one of claims 1 to 6, wherein the organosilicon compound is hexamethyldisiloxane. In a water-repellent treatment apparatus that performs water-repellent treatment on the substrate surface by forming the water-repellent thin film on the substrate surface using atmospheric pressure plasma chemical vapor deposition using an organosilicon compound as a raw material for the water-repellent thin film,
An atmospheric pressure plasma generator for generating atmospheric pressure plasma using a gas containing an inert gas and not containing an organosilicon compound;
A liquid material as a raw material for the water-repellent thin film, a mist supply device for mixing the raw material for the water-repellent thin film with the atmospheric pressure plasma using a mist
A water repellent treatment apparatus characterized by comprising:   The water repellent treatment apparatus according to claim 8, wherein a distance between the atmospheric pressure plasma and the substrate surface and a position where the mist is introduced into the atmospheric pressure plasma are variable.   The water repellent treatment apparatus according to claim 8 or 9, wherein the mist formation of the raw material of the water repellent thin film is performed using an ultrasonic vibrator. It further has a housing filled with an inert gas inside,
The generation of atmospheric pressure plasma by the atmospheric pressure plasma generator and the formation of the water-repellent thin film on the surface of the base material are performed inside the casing. 2. A water repellent treatment apparatus according to item 1.