Nova Patents
EP0743375A2

Method of producing diamond-like-carbon coatings

Abstract

A plasma enhanced chemical vapor deposition process is presented, wherein a precursor gas stream has a high helium content and produces hard, wear resistant, hermetically sealing, high refractive index Diamond-Like-Carbon (DLC) coatings on numerous substrates at relatively high deposition rates. The process may be applied to both batch and linear production methods. Linear products such as optical fibers, capillary tubing, wires, and sheets can be coated in-line while minimizing the introduction of flaws on their surfaces and minimizing exacerbation of any pre-existing flaws. The effects of surface flaws can be minimized further by introducing a helium etch of the substrate surface prior to exposure to the DLC coating precursor gas mixture. DLC coated products can be produced with the desired properties at commercially attractive deposition rates.

EP0743375A2, drawing sheet 1
Sheet 1 of 4

Term

Term ended

Projected expiry passed 25 March 2016, 10.5 years ago.

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10 claims: 6 independent, 4 dependent

  1. 1
    A method for producing Diamond-Like-Carbon (DLC) coatings on a substrate, said method characterized by introducing a substrate into a reaction chamber having an interior pressure between 1 and 10 Torr, mixing a carbonaceous reactant gas mixture with He to form a precursor gas with said precursor gas comprising at least 40% He by volume, facilitating deposition of the DLC coating onto the substrate by means of plasma created from said precursor gas and created by radio frequency inducing means in close proximity to said substrate, and flowing said precursor gas in said reaction chamber in close proximity to said substrate and said plasma-inducing means and at such a flow rate that a DLC coating is deposited on said substrate.
  2. 3
    The method of claims 1 or 2, which is further characterized by having said precursor gas being comprised of acetylene and He and being free of H 2 .
  3. 4
    The method of claims 1, 2 or 3, which is further characterized by operating said plasma-inducing means at a frequency between 30-50 kHz.
  4. 5
    The method of claims 1, 2, 3 or 4, which is further characterized by pretreating said substrate, after being introduced into an antechamber to said reaction chamber, in a plasma containing a gaseous mixture of He and residual air.
  5. 6
    A method for producing Diamond-Like-Carbon (DLC) coatings on a linear substrate, said method characterized by drawing of the linear substrate into a reaction chamber from a draw tower in a continuous stream through vacuum-containing gates with said reaction chamber having an interior pressure between 1 and 10 Torr, mixing a carbonaceous reactant gas mixture with He to form a precursor gas being at least 40% He by volume, facilitating deposition of the DLC coating onto the substrate by means of plasma created from said precursor gas and created by radio frequency inducing means in close proximity to said substrate, and flowing said precursor gas in said reaction chamber in close proximity to said substrate and said plasma-inducing means and at such a flow rate that a DLC coating is deposited on said substrate.
  6. 8
    The method of claims 6 or 7, which is further characterized by having said precursor gas being comprised of acetylene and He and being free of H 2 .
  7. 9
    The method of claims 6, 7 or 8, which is further characterized by operating said plasma-inducing means at a frequency between 30-50 kHz.
  8. 10
    The method of claims 6, 7, 8 or 9, which is further characterized by pretreating said substrate, after being introduced into an antechamber to said reaction chamber, in a plasma containing a gaseous mixture of He and residual air.
Independent claims8