Classifications

• • 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
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/40—Oxides
  • C23C16/407—Oxides of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• • 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
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/40—Oxides
• • 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
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/40—Oxides
  • C23C16/405—Oxides of refractory metals or yttrium
• • 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
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges

Definitions

• the present invention relates to plasma enhanced chemical vapor deposition of a metal oxide onto a substrate, particularly a plastic substrate.
• Metal oxide films are deposited onto glass substrates for a variety of applications.
• Shiozaki et al. describes a method for depositing a transparent electroconductive zinc oxide film onto the rear surface of a photoelectric converter using magnetron sputtering under high vacuum (2.2 mtorr).
• Siddle et al. describes a process for producing an electrically conductive low emissivity coating on a glass substrate comprising 1) depositing a reflective metal layer onto the substrate, then 2) reactive sputter depositing a metal oxide layer over the reflective metal layer in the presence of an oxygen scavenger, then 3) heat treating the substrate to 400° C to 720° C.
• the metal oxide is described as being an oxide of tin, zinc, tungsten, nickel, molybdenum, manganese, zirconium, vanadium, niobium, tantalum, cerium, or titanium or mixtures thereof.
• Woo in U.S. 6,603,033, describes the preparation of organotitanium precursors that can be used for metal-organic chemical vapor deposition (MOCND).
• MOCND metal-organic chemical vapor deposition
• the thin film of titanium oxide was described as being formed on a glass substrate that was heated to 375°C to 475° C.
• Hitchman et al. in WO 00/47797, describes the deposition of thin films of rutile titanium dioxide onto a variety of substrates including glass, sapphire, steel, aluminum, and magnesium oxide, at temperatures as low as 268° C, but at reduced pressures (1 torr).
• deposition of metal oxides onto temperature-resistant substrates such as glass can be carried out at relatively high temperatures without degrading the glass.
• significantly lower temperatures would be required to deposit a metal oxide onto a plastic substrate.
• the present invention addresses a need in the art by providing a method comprising the steps of 1) carrying a metal-oxide precursor through a corona discharge or a dielectric barrier discharge in the presence of an oxidizing agent to convert the precursor to a metal oxide by plasma enhanced chemical vapor deposition (PECND), and 2) depositing the metal oxide onto a substrate.
• a method comprising the steps of 1) carrying a metal-oxide precursor through a corona discharge or a dielectric barrier discharge in the presence of an oxidizing agent to convert the precursor to a metal oxide by plasma enhanced chemical vapor deposition (PECND), and 2) depositing the metal oxide onto a substrate.
• PECND plasma enhanced chemical vapor deposition
• organosiloxane and SiOx coating may be sequentially deposited or codeposited with metal oxides providing multilayer and/or composite compositions on the substrate.
• Fig. 1 illustrates a corona discharge method of generating and depositing a metal oxide on a substrate.
• Fig. 2 illustrates a dielectric barrier discharge device.
• the present invention is a method for depositing a metal oxide onto a substrate using plasma enhanced chemical vapor deposition.
• a metal-organic precursor is carried through a corona discharge or a dielectric barrier discharge in the presence of an oxidizing agent and preferably a carrier gas.
• the discharge converts the precursor to a metal oxide, which is deposited on a substrate.
• metal-oxide precursor refers to a material capable of forming a metal oxide when subjected to plasma enhanced chemical vapor deposition (PECND).
• metal-oxide precursors examples include diethyl zinc, dimethyl zinc, zinc acetate, titanium tetrachloride, dimethyltin diacetate, zinc acetylacetonate, zirconium hexafluoroacetylacetonate, zinc carbamate, trimethyl indium, triethyl indium, cerium (IN) (2,2,6,6-tetramethyl-3,5-heptanedionate), and mixtures thereof.
• metal oxides include oxides of zinc, tin, titanium, indium, cerium, and zirconium, and mixtures thereof.
• An example of a particularly useful mixed oxide is indium-tin-oxide (ITO), which can be used as a transparent conductive oxide for electronic applications.
• ITO indium-tin-oxide
• the method of the present invention can be advantageously carried out using well known corona discharge technology as illustrated in Fig. la.
• the headspace from precursor (10), a carrier for the precursor, and the oxidizing agent is flowed into the jet (20) through a first gas intake (30) and corona discharge (40) - which breaks down gas between two electrodes 50(a) and 50(b) - to form the metal oxide, which is deposited on the substrate (60), preferably a plastic substrate that is heated to impart order thereto.
• the plastic is advantageously maintained at a temperature near its T g , preferably not exceeding 50 C° higher than its T g , prior to and during the deposition of the metal oxide.
• the method is preferably carried out at or near atmospheric pressure, typically in the range of 700 - 800 torr.
• the carrier for the precursor is typically nitrogen, helium, or argon, with nitrogen being preferred;
• the oxidizing agent is an oxygen containing gas such as O 2 , ⁇ 2 O, air, O 3 , CO , NO, or N O , with air being preferred. If the precursor is highly reactive with the oxidizing agent - for example, if the precursor is pyrophoric - it is preferred to separate the oxidizing agent from the precursor, as depicted in Fig. lb.
• carrier and precursor are flowed through a second gas intake (70) situated just above the corona discharge (40) and the oxidizing agent is flowed through the first intake (30).
• a second carrier may be used to further dilute the concentration of the precursor prior to introduction into the jet (20).
• the oxidizing agent may not need to be affirmatively provided to the corona discharge or dielectric barrier discharge region if it is available to the region through the ambient air.
• the corona discharge (40) is preferably maintained at a voltage in the range of about 2 - 20 kN.
• the distance between the corona discharge (40) and the substrate (60) typically varies from about 1mm to 50 mm.
• the precursor can be delivered to the jet by partially filling a container with precursor to leave a headspace and sweeping the headspace with the carrier into the jet (10).
• the container can be heated, if necessary, to generate the desirable vapor pressure for the precursor.
• the precursor is moisture- or air-sensitive or both, it is preferable to hold the precursor in a substantially moisture-free and oxygen-free container.
• Dielectric barrier discharge also known as “silent” and “atmospheric-pressure- glow” discharges, can also be used to carry out the process of the present invention.
• Fig. 2 illustrates a schematic of a dielectric barrier discharge device (100), which comprises two metal electrodes (110 and 120) in which at least one is coated with a dielectric layer (130) superposed by a substrate (150).
• the gap between the electrodes (110 and 120) typically ranges from 1 to 100 mm and the applied voltage is on the order of 10-50 kN.
• the plasma (140) is generated through a series of micro-arcs that last for about 10-100 ns and that are randomly distributed in space and time.
• the concentration of the precursor in the total gas mixture (the precursor, the oxidizing agent, and the carrier gas) is preferably in the range of 10 ppm to 1% v/v.
• the flow rate of the precursor is preferably in the range of 0.1-10 seem and the flow rate of the oxidizing agent is preferably in the range of 10-100 scfin (2.7 x 10 5 to 2.7 x 10 6 seem).
• the thickness of the coating on the substrate is application dependent but is typically in the range! of 10 nm to 1 ⁇ m.
• the substrate is not limited but is preferably a plastic, examples of which include polycarbonates, polyurethanes, thermoplastic polyurethanes, poly(methylmefhacrylates), polypropylenes, low density polyethylenes, high density polyethylene, ethylene-alpha- olefin copolymers, styrene (co)polymers, styrene-acrylonitrile copolymers, polyethylene terephthalates, and polybutylene terephthalates.
• the method of the present invention can provide UN blocking coatings for plastic substrates at low temperature and at or near atmospheric pressure. The following examples are for illustrative purposes only and not intended to limit the scope of the invention.
• Dimethyltin diacetate was placed in a closed precursor reservoir and heated to 62° C. Nitrogen gas was passed through the reservoir at 3000 seem and combined with a stream of air passed at 15 scfin (420,000 seem). The outcoming gas line of the reservoir was heated to 70° C. The total gas mixture was passed tlirough a PLASM A- JET® corona discharge (available from Corotec Corp., Farmington, CT., electrode spacing of 1 cm) directed at a polycarbonate substrate. After 10 min., a clear monolithic coating of tin oxide was formed as evidenced by scanning electron microscopy and x-ray photoelectron spectroscopy (XPS).
• XPS x-ray photoelectron spectroscopy
• Titanium tetrachloride was placed in a closed precursor reservoir and cooled to 0° C. Nitrogen gas was flowed through the reservoir at 600 seem and combined with a stream of dry (TOC grade) air passed at 20 scfin (570,000 seem). The total gas mixture was passed through the plasma jet device directed at a polycarbonate substrate. After 8 min., a clear monolithic coating of titanium oxide was formed as evidenced by scanning electron microscopy and XPS.
• Example 3 Deposition of Zinc Oxide on a Polycarbonate Substrate
• Diethyl zinc was placed in a closed precursor reservoir. Nitrogen gas was passed through the reservoir at 150 seem and combined with another stream of nitrogen passed at 3500 seem. This gas mixture was introduced into a stream of air plasma generated by the plasma jet device and directed onto the polycarbonate substrate. The flow rate of the air (TOC grade) was 20 scfin (570,000 seem). After 10 min., a clear coating of zinc oxide was formed as evidenced by scanning electron microscopy and XPS.
• Example 4 Deposition of a UN absorbing Zinc Oxide on a Polycarbonate Substrate Diethyl zinc was placed in a closed precursor reservoir. Nitrogen gas was passed through the reservoir at lOOsccm and combined with another stream of nitrogen passed at 3800 seem. This gas mixture was introduced into a stream of air plasma generated by the plasma jet device and directed onto the polycarbonate substrate. The flow rate of the air (low humidity conditioned air) was 15 scfin (570,000sccm). The applied power to the electrodes was 720 W and the distance from jet to substrate was 20 mm. After 15 min, a clear coating of zinc oxide about 0.6 ⁇ m thick was formed on a polycarbonate sheet as evidenced by scanning electron microscopy and XPS.
• Nitrogen gas was passed through the reservoir at lOOsccm and combined with another stream of nitrogen passed at 3800 seem. This gas mixture was introduced into a stream of air plasma generated by the plasma jet device and directed onto the polycarbonate substrate. The flow rate of the air (low humidity conditioned
• the polycarbonate sheet (T g - 150° C) was heated to a temperature of 180° C to induce crystallinity in the coating, as evidenced by XRD analysis.
• Zinc oxide coatings were in tact after 1000 hours of QUV-B weathering tests according to ASTM G53-96. Coatings exhibited yellow Index ⁇ 5 and ⁇ 18% Delta Haze, 85% light transmission and a UN absorption cutoff of about 360 nm.
• Example 5 Deposition of Zinc Oxide Using a Dielectric Barrier Discharge on a Polycarbonate Substrate
• Diethylzinc was placed in a closed reservoir. Nitrogen gas was passed through the reservoir at 150sccm and combined with another stream of nitrogen at 60scfm. This gas mixture was introduced downstream and mixed with air prior to exiting the electrode into the discharge zone, which contacts the polycarbonate substrate. The flow rate of air was 11357sccm. The applied power to the electrodes was 1 ,000W and a distance from electrode to substrate was about 4mm. After lOmin, a clear coating of zinc oxide was formed on a polycarbonate film as evidenced by scanning electron microscopy and XPS.
• An organosiloxane coating similar to NPP according to patent US 5,718.967. was deposited onto a polycarbonate substrate.
• the precursor tetramethyldisiloxane flowing at 6000sccm is mixed with ⁇ 2O at a flowrate of lOOOsccm.
• This gas mixture was introduced into a stream of nitrogen plasma generated by the plasma jet device and directed onto the polycarbonate substrate.
• a balance gas of nitrogen is passed at a flowrate of 25 scfin.
• the applied power to the electrodes was 78W and the distance from jet to substrate was 5 mm.
• a Zinc Oxide coating was deposited on top of the organosiloxane coating according to Example 4.
• another organosiloxane layer was deposited on top of the Zinc Oxide layer.

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• 2005
  • 2005-05-20 EP EP05747858A patent/EP1756329A1/en not_active Withdrawn
  • 2005-05-20 MX MXPA06013380A patent/MXPA06013380A/es unknown
  • 2005-05-20 WO PCT/US2005/017747 patent/WO2005113856A1/en active Application Filing
  • 2005-05-20 CA CA002562914A patent/CA2562914A1/en not_active Abandoned
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