Method of ion beam milling substrate prior to depositing diamond like carbon layer thereon

• US 6,368,664 B1
• Filed: 11/02/2000
• Issued: 04/09/2002
• Est. Priority Date: 05/03/1999
• Status: Expired due to Term

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Petrmichl, Rudolph Hugo, Veerasamy, Vijayen S.
• Primary Examiner(s): CHEN, BRET P
• Application Number:
  US09/703,709
• Time in Patent Office: 523 Days
• Field of Search: 427/249.7, 427/249.15, 427/255.7, 427/307, 427/532, 427/533
• US Class Current: 427/249.7
• CPC Class Codes: B05D 5/083 involving the use of fluoropolymers
• CPC Class Codes: B08B 17/06 by giving articles subject to fouling a special shape or arrangement
• CPC Class Codes: B08B 17/065 the surface having a microscopic surface pattern to achieve the same effect as a lotus flower
• CPC Class Codes: B32B 17/1033 Laminated safety glass or glazing containing temporary protective coatings or layers
• CPC Class Codes: B60S 1/54 using gas, e.g. hot air
• CPC Class Codes: B60S 1/58 for rear windows
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: C03C 15/02 for making a smooth surface
• CPC Class Codes: C03C 17/22 with other inorganic material C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 17/3441 comprising carbon, a carbide or oxycarbide
• CPC Class Codes: C03C 17/3482 comprising silicon, hydrogenated silicon or a silicide
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3634 one layer at least containing carbon, a carbide or oxycarbide
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3652 the coating stack containing at least one sacrificial layer to protect the metal from oxidation
• CPC Class Codes: C03C 17/42 at least one coating of an organic material and at least one non-metal coating
• CPC Class Codes: C03C 19/00 Surface treatment of glass, not in the form of fibres or filaments, by mechanical means sand-blasting, grinding, or polishing glass B24
• CPC Class Codes: C03C 2217/282 Carbides, silicides
• CPC Class Codes: C03C 2217/76 Hydrophobic and oleophobic coatings
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C03C 2218/151 : by vacuum evaporation
• CPC Class Codes: C03C 2218/31 : Pre-treatment
• CPC Class Codes: C03C 23/006 : by plasma or corona discharge
• CPC Class Codes: C03C 23/0075 : Cleaning of glass specially adapted to plate glass B08B11/00
• CPC Class Codes: C03C 3/076 : with 40% to 90% silica, by weight C03C3/045 takes precedence
• CPC Class Codes: C23C 16/0272 : Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/26 : Deposition of carbon only

Abstract

A glass substrate is ion beam milled in order to smoothen the same and/or reduce or remove nano-cracks in the substrate surface before a coating system (e.g., diamond-like carbon (DLC) inclusive coating system) is deposited thereon. It has been found that such ion beam milling of the substrate prior to deposition of the coating system improves adherence of the coating system to the underlying milled substrate. Moreover, it has surprisingly been found that such ion beam milling of the substrate results in a more scratch resistant coated article when a DLC inclusive coating system is thereafter ion beam deposited on the milled substrate. Amounts sodium (Na) may also be reduced at the surface of the substrate by such milling.

Claims

1. A method of making a coated article comprising the steps of:

providing a glass substrate;

ion beam milling substantially an entire surface of the glass substrate so as to reduce the thickness of the substrate by at least about 2 Å

, wherein during the ion beam milling an ion beam is directed toward the glass substrate so as to hit the substrate at an angle Ω

of from about 40-60 degrees in order to mill the substrate for improving scratch resistance; and

depositing a coating system including at least one diamond-like carbon (DLC) inclusive layer directly on at least a portion of the ion beam milled surface of the substrate so as to contact the substrate following said ion beam milling step so as to form the coated article.

2. The method of claim 1, wherein said ion beam milling step is performed to an extent so as to increase scratch resistance (SR) of the coated article by at least a factor of two.

3. The method of claim 2, wherein said ion beam milling step is performed to an extent so as to increase the scratch resistance (SR) of the coated article by at least a factor of three.

4. The method of claim 1, wherein said ion beam milling step is performed in a manner so that an average surface roughness of the ion beam milled surface of the substrate following said ion beam milling is no more than about 80% of what an average surface roughness of the surface of the substrate was prior to said ion beam milling.

5. The method of claim 4, wherein said ion beam milling step is performed in a manner so that the average surface roughness of the ion beam milled surface of the substrate following said ion beam milling is no more than about 70% of what the average surface roughness of the surface of the substrate was prior to said ion beam milling.

6. The method of claim 5, wherein said ion beam milling step is performed in a manner so that the average surface roughness of the ion beam milled surface of the substrate following said ion beam milling is no more than about 60% of what the average surface roughness of the surface of the substrate was prior to said ion beam milling.

7. The method of claim 6, wherein said ion beam milling step is performed in a manner so that the average surface roughness of the ion beam milled surface of the substrate following said ion beam milling is no more than about 50% of what the average surface roughness of the surface of the substrate was prior to said ion beam milling.

8. The method of claim 1, wherein said ion beam milling step is performed so as to reduce the thickness of substantially the entire substrate by from about 2-100 Å

.

9. The method of claim 8, wherein said ion beam milling step is performed so as to reduce the thickness of substantially the entire substrate by from about 2-50 Å

.

10. The method of claim 9, wherein said ion beam milling step is performed so as to reduce the thickness of the entire substrate by from about 4-20 Å

.

11. The method of claim 1, further comprising using an inert gas in an ion beam source when performing said ion beam milling step, so that ions resulting from an inert gas are directed toward the substrate in order to mill the surface thereof.

12. The method of claim 1, further comprising using at least argon (Ar) ions to mill the surface of the substrate.

13. The method of claim 1, wherein said ion beam milling step is performed in a manner so that an elongated linear focused ion beam is used to mill the surface of the substrate.

14. The method of claim 1, wherein said ion beam milling step is performed in a manner so that after said ion beam milling step the atomic percentage (%) of sodium (Na) present in the first 20 Å

of the substrate adjacent the surface thereof is less than about 85% of what the atomic percentage (%) of sodium (Na) was in the first 20 Å

of the substrate adjacent the surface thereof prior to said ion beam milling step.

15. The method of claim 14, wherein said ion beam milling step is performed in a manner so that after said ion beam milling step the atomic percentage (%) of sodium (Na) present in the first 20 Å

of the substrate adjacent the surface thereof is less than about 75% of what the atomic percentage (%) of sodium (Na) was in the first 20 Å

of the substrate adjacent the surface thereof prior to said ion beam milling step.

16. The method of claim 1, wherein said ion beam milling step is performed in a manner so that after said ion beam milling step the atomic percentage (%) of sodium (Na) present in the first 75 Å

of the substrate adjacent the surface thereof is less than about 85% of what the atomic percentage (%) of sodium (Na) was in the first 75 Å

of the substrate adjacent the surface thereof prior to said ion beam milling step.

17. The method of claim 16, wherein said ion beam milling step is performed in a manner so that after said ion beam milling step the atomic percentage (%) of sodium (Na) present in the first 75 Å

of the substrate adjacent the surface thereof is less than about 75% of what the atomic percentage (%) of sodium (Na) was in the first 75 Å

of the substrate adjacent the surface thereof prior to said ion beam milling step.

18. The method of claim 1, wherein said ion beam milling step is performed in a manner so that after said ion beam milling step the atomic percentage (%) of sulfur (S) present in the first 20 Å

of the substrate adjacent the surface thereof is less than about 50% of what the atomic percentage (%) of sulfur (S) was in the first 20 Å

of the substrate adjacent the surface thereof prior to said ion beam milling step.

19. The method of claim 1, wherein said depositing a coating system step comprises forming a hydrophobic coating system on the substrate, the hydrophobic coating system including the DLC inclusive layer and at least one fluoro-alkyl silane (FAS) compound inclusive layer provided over the DLC inclusive layer;

and

forming the hydrophobic coating system so that the resulting coated article has an initial contact angle θ

of at least about 55 degrees with a drop of water, and an average hardness of at least about 10 GPa.

20. The method of claim 19, wherein the FAS compound includes at least one of:

CF₃(CH₂)₂Si(OCH₃)₃;

CF₃(CF₂)₅(CH₂)₂Si(OCH₂CH₃)₃;

CF₃(CH₂)₂SiCl₃;

CF₃(CF₂)₅(CH₂)₂SiCl₃;

CF₃(CF₂)₇(CH₂)₂Si(OCH₃)₃;

CF₃(CF₂)₅(CH₂)₂Si(OCH₃)₃;

CF₃(CF₂)₇(CH₂)₂SiCl₃;

CF₃(CF₂)₇(CH₂)₂SiCH₃Cl₂; and

CF₃(CF₂)₇(CH₂)₂SiCH₃(OCH₃)₂.

21. The method of claim 1, wherein the DLC inclusive layer includes sp³ carbon-carbon bonds.

22. The method of claim 1, wherein the coated article has an initial contact angle θ

of at least about 55 degrees with a drop of water.

23. The method of claim 22, wherein the coated article has an initial contact angle θ

of at least about 80 degrees with a drop of water.

24. The method of claim 1, further comprising depositing at least one intermediate layer SiO as to be located between the substrate and the DLC inclusive layer following said ion beam milling step.

25. The method of claim 1, wherein said depositing step is performed such that the DLC inclusive layer has an average hardness of at least about 20 GPa.

26. The method of claim 1, wherein said depositing step comprises ion beam depositing the DLC inclusive layer using at least a gas including silicon and carbon.

27. The method of claim 1, wherein the glass substrate comprises a soda-lime-silica glass substrate.

28. The method of claim 1, wherein the ion beam milling is performed using an ion energy of from about 1,500 to 2,000 eV.

29. A method of making a coated article comprising the steps of:

providing a substrate;

ion beam milling substantially an entire surface of the substrate so as to thin the substrate and smoothen the surface of the substrate, said ion beam milling being performed so as to reduce the thickness of at least a portion of the substrate by from about 4-20 Å

in order to improve scratch resistance; and

depositing a coating system on at least a portion of the ion beam milled surface of the substrate following said ion beam milling step so as to form the coated article.

30. The method of claim 29, wherein said ion beam milling step is performed to an extent so as to increase scratch resistance (SR) of the coated article by at least a factor of two.

31. The method of claim 29, wherein said ion beam milling step is performed in a manner so that an average surface roughness of the ion beam milled surface of the substrate following said ion beam milling is no more than about 80% of what an average surface roughness of the surface of the substrate was prior to said ion beam milling.

32. The method of claim 29, wherein said ion beam milling step is performed so as to reduce the thickness of the entire substrate by from about 4-20 Å

.

33. The method of claim 29, wherein said depositing step comprises ion beam depositing at least one DLC inclusive layer on the ion beam milled surface of the substrate.

34. The method of claim 29, wherein the substrate comprises a soda-lime-silica glass substrate.

35. The method of claim 29, wherein during the ion beam milling an ion beam is directed toward the glass substrate so as to hit the substrate at an angle Ω

of from about 40-60 degrees in order to mill the substrate.

36. A method of making a coated article comprising the steps of:

providing a glass substrate;

ion beam milling at least a portion of a surface of the glass substrate in order to make the surface more smooth and to reduce the thickness of at least a portion of the substrate by from about 4-20 Å

in order to improve scratch resistance; and

depositing a coating system including at least one diamond-like carbon (DLC) inclusive layer on at least a portion of the ion beam milled surface of the substrate following said ion beam milling step in forming the coated article.

37. The method of claim 36, wherein during the ion beam milling an ion beam is directed toward the glass substrate so as to hit the substrate at an angle Ω

of from about 40-60 degrees in order to mill the substrate.

38. The method of claim 36 wherein the ion beam milling is performed using an ion energy of from about 1,500 to 2,000 eV.

39. The method of claim 36, wherein said ion beam milling step is performed in a manner so that after said ion beam milling step the atomic percentage (%) of sulfur (S) present in the first 20 Å

of the substrate adjacent the surface thereof is less than about 50% of what the atomic percentage (%) of sulfur (S) was in the first 20 Å

of the substrate adjacent the surface thereof prior to said ion beam milling step.