Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
  • B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/60—Formation of materials, e.g. in the shape of layers or pillars of insulating materials
  • H10P14/65—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by treatments performed before or after the formation of the materials
  • H10P14/6502—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by treatments performed before or after the formation of the materials of treatments performed before formation of the materials
  • H10P14/6512—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by treatments performed before or after the formation of the materials of treatments performed before formation of the materials by exposure to a gas or vapour
  • H10P14/6514—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by treatments performed before or after the formation of the materials of treatments performed before formation of the materials by exposure to a gas or vapour by exposure to a plasma
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/20—Dry etching; Plasma etching; Reactive-ion etching
  • H10P50/24—Dry etching; Plasma etching; Reactive-ion etching of semiconductor materials
  • H10P50/242—Dry etching; Plasma etching; Reactive-ion etching of semiconductor materials of Group IV materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P70/00—Cleaning of wafers, substrates or parts of devices
  • H10P70/10—Cleaning before device manufacture, i.e. Begin-Of-Line process
  • H10P70/18—Cleaning before device manufacture, i.e. Begin-Of-Line process by combined dry cleaning and wet cleaning
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2/00—Disinfection or sterilisation of materials or objects, in general; Accessories therefor
  • A61L2/02—Disinfection or sterilisation of materials or objects, in general; Accessories therefor using physical processes
  • A61L2/14—Plasma, i.e. ionised gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
  • B01D2321/20—By influencing the flow
  • B01D2321/2066—Pulsated flow
  • B01D2321/2075—Ultrasonic treatment
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes

Definitions

• the present invention relates to a surface treatment method for an article having a hydrophilic surface, and an article surface-treated by the method.
• Oxygen gas or argon gas is brought into a plasma state under atmospheric pressure, and the plasma is sprayed onto the surface of a substrate such as a silicon wafer or a glass substrate for liquid crystal, so that organic substances adhering to the substrate surface are removed.
• a removal method is known (see Patent Documents 1 and 2). Also, atmospheric pressure plasma surface treatment equipment that has put this method into practical use has already been commercialized.
• a liquid such as an organic solvent containing an organic substance is irradiated with ultrasonic waves to generate bubbles in the liquid, and then the bubbles are irradiated with electromagnetic waves to generate plasma in the bubbles to generate plasma.
• Bubbles are generated in water by supplying a gas such as oxygen or air to water, and a high voltage pulse is applied to the bubbles to instantaneously change the inside of the bubbles to a plasma state.
• Patent Documents 4 to 9 describe techniques for decomposing organic matter with plasma.
• Patent Document 10 of (IV) describes that the surface modification of a fiber can be performed by bringing a plasma bubble into contact with the fiber.
• the material of the fiber is not particularly limited.
• the temperature of plasma bubbles is as high as about 5000 K, whereas organic polymer materials generally have sufficient heat resistance to withstand such high temperatures. Does not have sex.
• the melting point or soft spot of the material is lower than the temperature of the plasma bubble, it is expected that the material will melt and flow when it comes into contact with the plasma bubble, or even thermal decomposition and destruction will occur. It is difficult to apply plasma bubbles to fibers using various materials.
• Patent Document 1 Japanese Unexamined Patent Application Publication No. 2002-143795
• Patent Document 2 Japanese Patent Application Laid-Open No. 2004-311838
• Patent Document 3 Japanese Patent Application Laid-Open No. 2004-306029
• Patent Document 4 Japanese Translation of Special Publication 2005-502456
• Patent Document 5 Japanese Patent Laid-Open No. 2005-58887
• Patent Document 6 Japanese Unexamined Patent Application Publication No. 2005-21869
• Patent Document 7 Japanese Unexamined Patent Publication No. 2005-13858
• Patent Document 8 Japanese Patent Application Laid-Open No. 2004-268003
• Patent Document 9 Japanese Patent Laid-Open No. 2002-272825
• Patent Document 10 Japanese Patent Laid-Open No. 2005-105465
• An object of the present invention is to provide a surface treatment method capable of decomposing or removing organic matter such as dirt adhering to an article without being scattered in the atmosphere and suppressing damage to the article, while suppressing damage to the article.
• An object of the present invention is to provide a surface treatment method for etching the surface of an article and to provide an article that is not damaged while highly cleaning the surface and etching an article or surface that is hardly damaged.
• the surface treatment method of the present invention is characterized in that plasma generated in water vapor bubbles in a liquid containing water is brought into contact with a material having a contact angle with respect to water of 90 degrees or less in the liquid. .
• the article of the present invention is an article that has been surface-treated by the surface treatment method described above.
• the invention's effect is an article that has been surface-treated by the surface treatment method described above. The invention's effect
• the surface treatment method of the present invention it is possible to decompose or remove organic matter or the like adhering to an article without scattering it into the atmosphere, and to suppress damage to the article. Further, the surface of the article can be etched while suppressing damage to the article.
• the article obtained by the surface treatment method of the present invention has a highly cleaned or etched surface and is hardly damaged.
• FIG. 1 is a schematic configuration diagram showing an example of a plasma generator.
• FIG. 2 is a diagram showing the contact angle of water with the article surface.
• FIG. 3 is a graph showing the contact angle dependence of the etching rate due to water vapor bubbles in a plasma state (hereinafter referred to as water vapor bubble plasma).
• FIG. 4 is a schematic diagram of a multilayer wiring damascene process.
• FIG. 5 is a diagram showing an emission spectrum of water vapor bubble plasma force. (Example 1)
• FIG. 6 is an electron micrograph of the surface of a clogged hollow fiber membrane sample.
• FIG. 7 is an electron micrograph of the surface of a hollow fiber membrane sample after surface treatment.
• the surface treatment method of the present invention is a method in which plasma generated in water vapor bubbles in a liquid containing water is brought into contact with an article having a hydrophilic surface in the liquid.
• the index of the hydrophilic material in the present invention is a material having a contact angle with water of 90 degrees or less.
• Japanese Patent Application Laid-Open No. 2003-297598 A plasma generator described in JP 2004-152523 A may be used.
• FIG. 1 is a schematic configuration diagram showing an example of a plasma generator used in the surface treatment method of the present invention.
• the plasma generator 10 includes a container 12 for storing a liquid 11, an electrode 13 for radiating electromagnetic waves disposed in the container 12, and a counter electrode 14 disposed to face the electrode 13.
• a vacuum pump (not shown) for adjusting the pressure of the air phase 19 (gas phase) above the liquid 11 is generally configured.
• the electrode 13 is connected to an electromagnetic wave power source capable of supplying a high frequency and a high voltage.
• an electromagnetic wave power source capable of supplying a high frequency and a high voltage.
• Water vapor bubble plasma Light emission appears in a specific wavelength region from water vapor bubbles in a plasma state (hereinafter referred to as water vapor bubble plasma). From this emission spectrum, it is possible to know the type of gas that is generated inside the plasma bubble. Table 1 shows the wavelength of the emission spectrum of water vapor bubble plasma and the attribution of the type of gas that is the cause of light emission.
• the liquid 11 may be a liquid containing water, and examples thereof include water, an aqueous solution containing an organic solvent mixed with water, and an aqueous solution in which electrolyte ions are dissolved in water.
• Examples of the organic solvent mixed with water include alcohols such as methanol, ethanol, isopropyl alcohol and butanol; acetone and the like.
• Examples of the electrolyte ions include Mg 2+ , Ca 2+ , Na + , Fe 2+ , Fe 3+ , CI ", NO 3- , NO 2 ", OH "and the like.
• the presence of electrolyte ions in the liquid 11 improves the electrical conductivity of water, and an arc discharge current easily flows from the electrode 13 that emits electromagnetic waves to the counter electrode 14 when plasma is generated.
• the organic solvent may be carbonized by plasma and the carbide may adhere to the article 15.
• the liquid 11 does not contain an organic solvent as much as possible. More preferably, it is desirable to use pure water or ultrapure water used in a semiconductor manufacturing process.
• the generation of water vapor bubbles 17 is not limited to the method of heating the electrode 13, In this method, a wave generation device is provided, and cavity bubbles are generated in the liquid 11 by ultrasonic waves from the ultrasonic generation device, and the surrounding liquid 11 is vaporized as vapor in the bubbles to form the water vapor bubble 17.
• a wave generation device is provided, and cavity bubbles are generated in the liquid 11 by ultrasonic waves from the ultrasonic generation device, and the surrounding liquid 11 is vaporized as vapor in the bubbles to form the water vapor bubble 17.
• the frequency of the electromagnetic wave applied to the water vapor bubbles 17 is selected in the range of lMHz to 100GHz according to the application.
• the air phase 19 in the container 12 may be depressurized by a vacuum pump.
• the air phase 19 in the container 12 is depressurized, the boiling point of the liquid 11 decreases, water vapor is more likely to be generated, the vapor pressure inside the water vapor bubbles increases, and the number of water vapor molecules leading to plasma generation increases. Therefore, plasma discharge becomes easy.
• plasma generation inside the bubble continues even after the vacuum pump is stopped and the pressure of the air phase 19 is returned to atmospheric pressure.
• an article having a hydrophilic surface is suitable. Specifically, a hydrophilic organic polymer material, glass, ceramics, silicon wafer, metal (for example, aluminum, copper, tandastene, etc.) , Graphite, carbon fiber and the like.
• the “hydrophilic surface” is defined as having the value of the contact angle ⁇ defined in FIG.
• the “hydrophilic surface” in the present invention is a surface having a contact angle ⁇ of water (water droplet 18) with respect to the surface of the article 15 at 90 ° C. or less at 25 ° C.
• the contact angle of water with the hydrophilic surface is preferably as low as possible, specifically 80 ° or less, more preferably in the range of 70 ° to 0 °.
• the definition of the contact angle ⁇ in the present invention is the same as the contact angle, which is a general indicator of the wetting of the material with respect to water.
• the contact angle which is a general indicator of the wetting of the material with respect to water.
• I quote the items described in “Molding Surface”, published by Modern Editor, 1984, p. 133.
• the following equation (1) is established in FIG.
• the contact angle ⁇ of the water droplet is used to quantify the elasticity is based on the equation (2).
• the liquid is water, and ⁇ is 72.8 dynZcm (“Science Chronology”) at 20 ° C.
• a smooth material surface is prepared, this surface is kept horizontal, water drops are dropped on the surface, ( ⁇ Z2) is measured with a contact angle meter, and the contact angle in FIG. Find ⁇ .
• the material surface is porous or has irregularities, prepare a smooth surface with the same material, and calculate ⁇ on the smooth surface.
• a smooth surface can be obtained by melting the same material.
• a smooth sheet that also has a precursor material for example, polyacrylonitrile or polyimide
• the water used in the measurement of contact angle is clean water such as ultrapure water and ion exchange water.
• Biocompatible material Hydrogel (Ref. B 5)
• Biocompatible materials Cellulose and poly (bull alcohol) (reference b 6)
• the solid surface tension of ⁇ -Fe is 1670-2127dyn /
• the solid surface tension of cm, copper is about 1500 dynZcm, which is described to be much larger than the surface tension of polymers. It is.
• the surface tension of water is 72.8 dynZcm. That is, the surface of a clean metal is a surface that is very wettable with water.
• the surface treatment of the present invention can be applied to a clean metal material having a high surface energy.
• any material such as an organic polymer material, glass, ceramics, metal, graphitic carbon material, carbon fiber and the like can be applied as long as ⁇ 90 degrees is satisfied.
• the temperature is as high as about 5000 K. If the high temperature plasma gas mentioned above is brought into contact, it will be instantly destroyed without a trace.
• the present inventors can clean by decomposing or removing only the organic matter on the article surface that hardly damages the article surface. The present inventors have found that the surface cleaned can be etched without destroying the cleaned article.
• FIG. 3 The idea of the present invention to avoid thermal decomposition is schematically shown in FIG. As shown in Fig. 3, when the material is brought into contact with water vapor bubbles in water, if the contact angle ⁇ of the material with respect to water is 90 degrees or less, the contribution of thermal decomposition etching is reduced to 90 degrees. It has been found that the contribution of pyrolytic etching increases beyond this range. The reason for this phenomenon is as follows.
• a material having a ⁇ force of 3 ⁇ 40 degrees or less has its surface covered with a water layer in a liquid containing water, and even when water vapor bubble plasma approaches, the water on the surface of the material evaporates, It takes away the latent heat of evaporation from the surroundings of the material, and water is constantly supplied to the hydrophilic surface, so that a permanent cooling effect acts on the material surface and the temperature rise of the article is suppressed.
• the surface temperature of the article does not exceed the heat resistance temperature of the material, the contribution of etching by thermal decomposition is reduced, and damage to the material is suppressed. This effect is also effective in preventing excessive graphite defects locally due to the heat of plasma in the surface treatment of carbon fibers.
• the dirt on the surface of the material is decomposed under the action of thermal decomposition of the water vapor bubble plasma by heat and decomposition of acid / sodium by OH radicals.
• the dirt disappears, a more hydrophilic surface of the material appears, and the above-described cooling effect of water suppresses thermal decomposition, resulting in a material surface with low damage.
• hydrophilic material having a contact angle of 90 or less
• etching by thermal decomposition can be suppressed, and the material can be gradually etched by acid decomposition by OH radicals.
• various materials exhibiting hydrophilicity can be etched.
• hydrophilic polymer materials, metal materials, ceramics, hydrophilic glass, and hydrophilic carbon materials can be etched.
• the time for which the article 15 is brought into contact with the water vapor bubble plasma (hereinafter referred to as the contact time) is the heat resistance temperature of the article 15, the temperature inside the bubble plasma, the water generated on the article surface. Adjust as appropriate, taking into account the cooling effect and the degree of dirt.
• the “contact time” in the present invention is defined as the time during which plasma is generated in the water vapor bubbles 17 by applying a voltage to the electrode 13 and the counter electrode 14 when the article 15 is stationary. However, when the article 15 is moving in a certain direction, it is defined as follows.
• the index of the heat resistant temperature of the material varies depending on the type of the material, but in the present invention, the heat resistant temperature is defined as the temperature at which the form of the material can be maintained.
• the melting point is used as an index of the heat resistant temperature.
• Table 5 shows the melting point (Tm) of typical ceramics. (Marcel Mulder, “Basic Principles of Membrane Technology J, 2nd Edition ⁇ Kluwer Academic Publishers ⁇ 1996, p. 60)
• the glass transition temperature is used as an index of the heat resistant temperature.
• Table 6 shows the glass transition temperatures of typical optical glass types.
• the melting point of the material is used as an index of the heat resistant temperature.
• Table 7 shows the melting points of typical optical crystal materials.
• the melting point is used as an index of the heat resistant temperature.
• Table 8 shows the melting points of typical metals. (National Astronomical Observatory of Japan, “Science Chronology”, Maruzen Co., Ltd., 1993, p.469)
• the surface treatment method of the present invention comprises (1) cleaning an article in which organic matter such as dirt adheres (deposits) on the material surface, (2) processing for etching the hydrophilic material surface, and (3) unevenness on the material surface. It can be applied to processing that gives
• Organic substances include viruses, bacteria, yeast, mold, algae, protozoa, proteins, blood and blood components, animal or plant cells, hair, living garbage, garbage, wastewater, etc. Organic materials that are commonly found in daily life are listed.
• Examples of the cleaning of the article based on the surface treatment method of the present invention include the following examples.
• the target of cleaning is not limited to the following examples. Any hydrophilic material that has a water contact angle of ⁇ force or less can be used. If it is selected appropriately, it can be washed.
• Plasma is brought into contact with the porous membrane having a hydrophilic surface used for the filtration treatment, and the filtration deposits such as organic matter adhering to the membrane surface are converted into thermal decomposition (or carbonization) or OH radicals.
• the porous film is regenerated by decomposing and removing by the oxidizing action.
• the plasma After being embedded in the human body, the plasma is brought into contact with the biocompatible material having a hydrophilic surface, which is removed from the human body, and the organic matter attached to the biocompatible material surface is thermally decomposed (or It is decomposed and removed by oxidation by carbonization and OH radicals to regenerate biocompatible materials.
• the biocompatible material include polymethylmetatalate rosin, polylactic acid rosin, polyuretan, hydrogel, cellulose, polybulal alcohol, and hydroxyapatite.
• Plasma is brought into contact with an organ having a hydrophilic surface that has been removed from the human body, and cancer cells present in the organ are separated by thermal decomposition (or carbonization) or acid-oxidation by OH radicals. Remove the solution.
• Plasma is brought into contact with a contact lens having a hydrophilic surface, and organic substances such as proteins adhering to the contact lens are decomposed and removed by thermal decomposition (or carbonization) or acid operation with OH radicals.
• the catheter or artificial blood vessel having a hydrophilic surface Before embedding in the human body, the catheter or artificial blood vessel having a hydrophilic surface is brought into contact with the plasma, and the catheter or artificial blood vessel is sterilized or removed from the human body. Plasma is brought into contact with an artificial blood vessel, which is decomposed and removed by thermal decomposition (or carbonization) or oxidation by OH radicals. After disassembly and removal, safely discard the catheter or artificial blood vessel.
• a plasma is brought into contact with a DNA sample detection device having a hydrophilic surface before or after use, and organic substances on the surface of the device are thermally decomposed (or carbonized) or oxidized by OH radicals. Decompose and remove.
• Plasma is brought into contact with the nonwoven fabric having a hydrophilic surface, and the organic matter adhering to the nonwoven fabric surface is decomposed and removed by thermal decomposition (or carbonization) or oxidation action by OH radicals.
• (H) Lithographic material force such as photoresist thin film The surface of the silicon wafer coated on the surface is brought into contact with water vapor bubble plasma to remove the thin film. Alternatively, clean the dirt on the silicon wafer by bringing water vapor bubble plasma into contact with the silicon wafer with dirt on the surface.
• the surface of the carbon electrode modified to a hydrophilic surface is cleaned by this technique.
• a hydrophilic electrode is used in some cases. Due to repeated charging and discharging, dirt may be generated in the electrolyte solution, and dirt may be generated on the electrode surface. According to the present invention, it is possible to clean a carbon electrode to which dirt is attached.
• a fluorine-based electrolyte membrane for example, a naphthion membrane manufactured by DuPont
• a fluorine-based electrolyte membrane used as a solid electrolyte membrane is highly hydrophobic.
• the moisture content of the membrane increases and the contact angle with water decreases.
• a membrane surface with a contact angle of 90 degrees or less can be cleaned by the technique of the present invention.
• Examples of the above-described (2) processing for etching the surface of the hydrophilic material include the following examples.
• FIG. 4 shows a schematic diagram of the damascene process. In Fig. 4, the process proceeds from a ⁇ b ⁇ c, and the wiring metal pattern is formed at c.
• the metal atom is converted to an atomic level by an electrochemical reaction between atomic hydrogen and OH radicals generated from water vapor bubble plasma and the metal atom. It can be processed precisely while removing with. In that case, it is necessary to appropriately control the etching rate by OH radicals.
• the silicon wafer is immersed in water in the reactor shown in Fig. 1, and the silicon wafer is brought into contact with the water vapor bubble plasma while rotating the silicon wafer in water. Can be washed.
• porous membrane examples include a hollow fiber membrane, a flat membrane, a tubular membrane, etc., made of hydrophilic polyethylene.
• a dirty porous membrane is immersed in water and fixed in the vicinity of an electrode that emits electromagnetic waves.
• electromagnetic waves When electromagnetic waves are radiated from the electrode, water vapor bubbles are generated around the electrode, and at the same time, plasma is generated in the water vapor bubbles.
• the plasma generated in the water vapor bubbles is brought into contact with the membrane surface of the porous membrane for a predetermined contact time, the organic matter adhering to the membrane surface is thermally decomposed by the plasma. And blown away.
• the hydrophilic surface that is exposed after the organic matter is blown away is covered with a layer of water because it is easily wetted with water, and the pore structure formed in the porous membrane that is not easily damaged by plasma is almost maintained.
• the contact time is preferably 1-5 minutes.
• the contact time is less than 1 minute, organic substances such as dirt attached to the porous membrane surface may not be sufficiently removed. If the contact time exceeds 5 minutes, a part of the porous membrane surface starts to melt.
• the dirt can be cleaned in the same manner.
• the present invention can also be applied to the etching of (n) to (o).
• the surface treatment method of the present invention can also be applied to partial etching of articles. That is, when plasma is brought into contact with an article having both a hydrophobic surface ( ⁇ > 90 degrees) and a hydrophilic surface ( ⁇ ⁇ 90 degrees) in water, the etching rate of the hydrophobic surface increases. Unevenness is formed on the surface of the article.
• This concavo-convex formation technology is used for etching materials in semiconductor lithographic processes, fine concavo-convex processing of plastic materials (for example, to provide a non-glare function for preventing image reflection on the surface of a transparent resin plate). It is useful for processing.
• the surface of the article is brought into contact with the water vapor bubble plasma in the liquid, so that the decomposed product of the article power is not scattered in the atmosphere. .
• it can be safely decomposed and removed in water without scattering viruses, harmful organic substances, etc. into the atmosphere.
• the decomposition product that has moved into the water can be safely removed from the water by collecting it with an adsorption filter.
• articles handled at hospitals and other medical sites and food manufacturing sites for example, catheters, artificial blood vessels, DNA specimen detection devices, nonwoven fabrics that capture viruses, dialysis filtration membranes, microfiltration membranes, gas separation membranes, etc.
• the present invention is effective for this purpose.
• a household water purifier (trade name: Krinsi 02) manufactured by Mitsubishi Rayon Co., Ltd. was prepared.
• the hollow fiber membrane is a hollow fiber membrane manufactured by Mitsubishi Rayon Co., Ltd. having an inner diameter of 270 m and a film thickness of 55 m. Fibrils that have polyethylene strength are oriented in the fiber direction of the hollow fiber membrane, and the fibrils are the membranes. It has a slit-shaped pore structure in which many layers are stacked in the thickness direction.
• the clogged hollow fiber membrane sample was as short as about 50 mm, the clogged hollow fiber membrane was made into a 150 mm long hydrophilized hollow fiber membrane (EX-540V polyethylene hollow fiber membrane manufactured by Mitsubishi Rayon). A sample for experiment was prepared by attaching samples.
• the apparatus shown in Fig. 1 was used as the plasma generating apparatus.
• the RF power supply is THAMW AY, model T161-5766LQ, and the matching box is THAMWAY Model T0202-5766LQ, manufactured by KK, was used.
• Example 9 Using the same plasma generator as in Example 1, an experimental sample was immersed in a water-filled container and fixed with a support near the electrode. A water vapor bubble plasma was generated under the same conditions as in Example 1 except that an ethylene butyl alcohol copolymer film (hereinafter also referred to as an EVAL film) shown in Table 9 was used as a sample. Was in contact with the sample for 3 minutes. All films had a contact angle with water before plasma contact within a range of 64 to 71 degrees and exhibited hydrophilicity. All of these films withstood the heat of the water vapor bubble plasma and maintained their morphology.
• EVAL film ethylene butyl alcohol copolymer film
• CA-DT made by Kyowa Interface Science is used for the contact angle meter.
• the pure water droplet volume was 1 ⁇ m.
• “Plasma durability” means durability against water vapor bubble plasma in water.
• FIG. 1 “The gas phase is atmospheric pressure” in FIG. 1 means that the gas phase above the water surface is air at atmospheric pressure, and water vapor bubble plasma was generated in this state.
• the surface of the film of sample DC3203F was marked with oil-based ink.
• Ma When the king was applied to the plasma, the oil-based ink was decomposed by the plasma, and the remaining power on the film was strong. The film surface after washing was smooth by visual observation.
• Example 10 Using the same plasma generator as in Example 1, the sample was immersed in a container filled with water, and the sample was fixed with a support near the electrode. Next, water vapor bubble plasma was generated under the same conditions as in Example 1, and the plasma was brought into contact with the sample for 3 minutes. As shown in Table 10, both Nafionl 12 and Nafionl 035 swollen with water resisted the heat of water vapor bubble plasma and maintained their morphology.
• the surface of the Nafionl 12 film was marked with oil-based ink.
• the marking was firmly attached to the film.
• oil-based ink was decomposed by plasma. There was no remaining force on the sample.
• the film surface after cleaning was smooth by visual observation.o
• Example 2 Using the same plasma generator as in Example 1, the sample was immersed in a water-filled container and fixed with a support near the electrode. A vapor bubble plasma was generated under the same conditions as in Example 1 except that an optically polished glass plate (thickness 5 mm, 100 mm ⁇ 100 mm) was used as a sample, and the plasma was brought into contact with the glass plate for 3 minutes. It was. The glass plate withstood the heat of water vapor bubble plasma and maintained its form. The contact angle of the glass plate with water before contact with the plasma was about 35 degrees.
• the surface of the glass plate was marked with oil-based ink, and the marked portion was visually observed after contacting the water vapor bubble plasma in water for 3 minutes.
• the oil-based ink was decomposed by the plasma and had a strong force remaining on the glass plate.
• the glass plate after washing was smooth by visual inspection.
• Example 2 Using the same plasma generator as in Example 1, an experimental sample was immersed in a water-filled container and fixed with a support near the electrode. As a sample, alumina ceramic sheet ( ⁇ -A1
• the surface of the alumina ceramic sheet was marked with oil-based ink, and the marked portion was contacted with water vapor bubble plasma in water for 3 minutes and then visually observed.
• the oil-based ink was decomposed by the plasma and remained on the alumina ceramic sheet.
• the surface of the alumina ceramic sheet after washing was smooth by visual observation.
• Example 2 Using the same plasma generator as in Example 1, an experimental sample was immersed in a water-filled container and fixed with a support near the electrode. Using an ethylene-butyl alcohol copolymer film (ethylene content 32 mol%) as a base material (thickness 3 mm, 100 mm x 100 mm), a 5 mm wide polyethylene film (thickness 0.5 mm, 100 mm x 100 mm) is spaced apart from this base material. A sample having a hydrophilic surface Z hydrophobic surface force of 5 mm width and a hydrophobic portion 5 mm width was prepared by attaching 5 mm apart and heat-sealing.
• ethylene-butyl alcohol copolymer film ethylene content 32 mol%
• the contact angle of ethylene-butyl alcohol copolymer film (ethylene content 32 mol%) with water was 67 °, and the contact angle of polyethylene film with water was 95 °.
• a vapor bubble plasma was generated in the same manner as in Example 1 except that the prepared sample was used, and the plasma was brought into contact with the entire sample for 3 minutes.
• the polyethylene film which is a hydrophobic part, was etched by plasma and the average thickness was 0.1 mm. Maintained a smooth initial surface. Only the hydrophobic part was the result of being etched by the plasma.
• the surface of these films did not adhere to organic substances such as dirt.
• These films were subjected to surface treatment in the same manner as in Example 1. Both films were thermally decomposed by the high temperature of the plasma at the moment when the plasma contacted, and broke.
• Example 3 Under the same conditions as in Example 3, except that two types of Nafion membranes (Nafionl 12, Nafionl 035) manufactured by DuPont, which were left in an atmosphere of 55% RH for one week, were used as samples. Bubble plasma was contacted.
• Example 2 Prepare 200 mL of pure water in a 300 mL beaker and use the clogged hollow fiber membrane 25 used in Example 1.
• the hollow fiber membrane was washed for 1 hour in an ultrasonic cleaner with an output of 100W and 20KHz. When the washed film was observed with an electron microscope, the organic matter clogged on the film surface was not removed, and it was strong.
• Example 1 the electrode of the reactor was overheated to generate water vapor bubbles that were not in a plasma state and contacted with the hollow fiber membrane sample clogged with the water vapor bubbles for 3 minutes. The membrane surface was clogged. Organic matter was a force that had not been removed.
• the present invention decomposes organic substances adhering to an article without damaging the article by bringing the plasma generated in water vapor bubbles into contact with the article having a hydrophilic surface in water. Or it is a surface treatment technique to remove.
• This surface treatment technology is useful, for example, for household water purifiers, industrial wastewater filtration, organic polymer porous membranes used for air filtration, ceramic porous membrane regeneration, and safe disposal of porous membranes.
• membranes that are contaminated or clogged with substances containing bacteria such as filtration membranes for hospital hand-washing water, air filtration membranes for hospital infection prevention in hospitals, and air filtration membranes for biohazard rooms, can be safely regenerated or It is an effective method for disposal.
• the surface treatment method of the present invention uses a biocompatible material embedded in the body, and after use, organic matter such as bacteria on the surface of the material is pyrolyzed or carbonized to safely dispose of the material.
• organic matter such as bacteria on the surface of the material is pyrolyzed or carbonized to safely dispose of the material.
• the surface treatment method of the present invention is used for sterilization of catheters, artificial blood vessels before being embedded in the body, sterilization of fungi that adhere after removal from the living body; Treatment to remove bacteria from bacteria; Treatment to safely dispose of used DNA sample detection devices; Safely by pyrolyzing or carbonizing fungi attached to non-woven fabric used in air filters, masks, etc. It can also be applied to processing for disposal.
• the etching technique of the present invention gives fine irregularities to the surface of a hydrophilic transparent organic material, exhibits an antireflection function in optical applications, and exhibits visibility only at a specific viewing angle. It can also be used for processing into a privacy filter. Furthermore, the surface of the metal film can be etched only with chemical species derived from water molecules, and the cost of waste liquid treatment can be reduced in the damascene process of high-density multilayer wiring in semiconductor devices, thus reducing manufacturing costs. It is effective for.
• the hydrophobic portion can be selectively etched by controlling the contact time with the water vapor bubble plasma to make it short.
• This technology can be applied to selectively etch the hydrophobic portion of various materials such as organic materials, inorganic materials, and carbon materials that have both a hydrophilic surface and a hydrophobic surface portion.
• materials such as carbon materials and silicon wafers are difficult to surface-process because of their high heat-resistant temperature, but the etching power can be easily obtained by using this technique.

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