Ion beam process for deposition of highly abrasion-resistant coatings

Abstract

An ion beam deposition method is provided for manufacturing a coated substrate with improved abrasion resistance, and improved lifetime. According to the method, the substrate is first chemically cleaned to remove contaminants. In the second step, the substrate is inserted into a vacuum chamber, and the air in said chamber is evacuated. In the third step, the substrate surface is bombarded with energetic ions to assist in the removal of residual hydrocarbons and surface oxides, and to activate the surface. Alter After the substrate surface has been sputter-etched, a protective, abrasion-resistant coating is deposited by ion beam deposition. The ion beam-deposited coating may contain one or more layers. Once the chosen thickness of the coating has been achieved, the deposition process on the substrates is terminated, the vacuum chamber pressure is increased to atmospheric pressure, and the coated substrate products having improved abrasion-resistance are removed from the vacuum chamber. The coated products of this invention have utility as plastic sunglass lenses, ophthalmic lenses, bar codes scanner windows, and industrial wear parts that must be protected from scratches and abrasion.

What is claimed is:  
     
       1. A method for producing an optically transparent coating on the surface of a substrate comprising: 
       (a) chemically cleaning the surface of said substrate to remove residual hydrocarbons and other contaminants;  
       (b) mounting said substrate in a deposition vacuum chamber and evacuating the air from said chamber,  
       (c) sputter-etching the surface of said substrate with a beam of ions to further remove residual hydrocarbons and other surface contaminants, and to activate the surface;  
       (d) plasma ion beam depositing using precursor gases at least one layer of a material selected from the group consisting of an amorphous silicon carbide, silicon nitride, silicon oxide, silicon oxy-nitride, silicon oxy-carbide, silicon carbonitride, and silicon oxy-carbonitride and using a gridless ion source having a plasma chamber therein, wherein a plasma is generated in the plasma chamber and a gas stream containing at least a portion of said precursor gases is introduced outside of the ion source and into the plasma ion beam;  
       (e) increasing the vacuum chamber pressure to atmospheric pressure; and  
       (f) recovering a coated substrate product with an abrasion resistance greater than or about equal to the abrasion resistance of glass lenses.  
     
     
       2. The method of claim  1  wherein said gridless ion source is selected from the group consisting of an End Hall ion source and a Hall accelerator ion source. 
     
     
       3. The method of claim  1  wherein said substrate comprises a material selected from the group consisting of a plastic, a metal, a glass and a ceramic. 
     
     
       4. The method of claim  2  wherein said substrate comprises a material selected from the group consisting of a plastic, a metal, a glass and a ceramic. 
     
     
       5. The method of claim  1  wherein said substrate is an optically transparent material. 
     
     
       6. The method of claim  2  wherein said substrate is an optically transparent material. 
     
     
       7. The method of claim  1  wherein said substrate is an optically transparent lens. 
     
     
       8. The method of claim  2  wherein said substrate is an optically transparent lens. 
     
     
       9. The method of claim  5  wherein said substrate is a bar code scanner window. 
     
     
       10. The method of claim  6  wherein said substrate is a bar code scanner window. 
     
     
       11. The method of claim  1  wherein said substrate material is silicon or germanium. 
     
     
       12. The method of claim  1  wherein said abrasion-resistant coating includes multiple layers of at least two different refractive indices to reduce reflection. 
     
     
       13. The method of claim  1  wherein said abrasion-resistant coating includes multiple layers of at least two different refractive indices to reduce reflection. 
     
     
       14. The method of claim  7  wherein said abrasion-resistant coating includes multiple layers of at least two different refractive indices to reduce reflection. 
     
     
       15. The method of claim  8  wherein said abrasion-resistant coating includes multiple layers of at least two different refractive indices to reduce reflection. 
     
     
       16. A method for depositing onto a parent substrate an optically transparent coating material consisting of C, H, Si and O which comprises: 
       (a) chemically cleaning the surface of said substrate to remove residual hydrocarbons and other contaminants;  
       (b) mounting said substrate in a deposition vacuum chamber and evacuating the air from said chamber;  
       (c) sputter-etching the surface of said substrate with a beam of ions to further remove residual hydrocarbons and other surface contaminants, and to activate the surface;  
       (d) plasma ion beam depositing onto the surface of said substrate a layer of said optically transparent coating material by exposing said substrate to precursor gases containing carbon, hydrogen, silicon and oxygen, whereby said precursor gases are activated by said plasma ion beam and said substrate is bombarded by ions during the deposition, using a gridless ion source having a plasma chamber therein, wherein a plasma is generated in the plasma chamber and a gas stream containing at least a portion of said precursor gases is introduced outside of the ion source and into the plasma ion beam;  
       (e) increasing the vacuum chamber pressure to atmospheric pressure; and  
       (f) recovering a product having an abrasion resistance greater than or about equal to the abrasion resistance of glass lenses and coated with said optically transparent coating material having the properties of a Nanoindentation hardness in the range of about 2 to about 5 Giga Pascals and a tensile strain required to produce microcracking in said material of greater than about 1%.  
     
     
       17. The method of claim  16  wherein said precursor gases also contain nitrogen and said optically transparent coating material also contains nitrogen and has an abrasion resistance greater than or equal to the abrasion resistance of glass lenses. 
     
     
       18. The method of claim  16  wherein a portion of said precursor gases are introduced into the plasma chamber of the ion source, and the remaining portion of said precursor gases are introduced outside of the ion source plasma chamber and into the ion beam. 
     
     
       19. The method of claim  16  wherein said precursor gases contain oxygen. 
     
     
       20. The method of claim  16  wherein said precursor gases comprise materials selected from the group consisting of siloxanes, silanes, silazanes, and mixtures thereof. 
     
     
       21. The method of claim  16  wherein said precursor gases comprise materials selected from the group consisting of hexamethyldisiloxane, tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane and mixtures thereof. 
     
     
       22. A method for depositing onto a parent substrate an optically transparent coating material consisting of C, H, Si and O which comprise: 
       (a) chemically cleaning the surface of said substrate to remove residual hydrocarbons and other contaminants;  
       (b) mounting said substrate in a deposition vacuum chamber and evacuating the air from said chamber;  
       (c) sputter-etching the surface of said substrate with a beam of ions to further remove residual hydrocarbons and other surface contaminants, and to activate the surface;  
       (d) plasma ion beam depositing onto the surface of said substrate an interlayer of said optically transparent coating material having the properties of a Nanoindentation hardness in the range of about 2 to about 5 Giga Pascals and a tensile strain required to produce microcracking in said material of greater than about 1% by exposing said substrate to precursor gases containing carbon, hydrogen, silicon and oxygen, whereby said precursor gases are activated by said plasma ion beam and said substrate is bombarded by ions during the deposition, using a gridless ion source having a plasma chamber therein, wherein a plasma is generated in the plasma chamber and a gas stream containing at least a portion of said precursor gases is introduced outside of the ion source and into the plasma ion beam;  
       (e) depositing onto said interlayer a layer of abrasion-resistance diamond-like carbon coating material;  
       (f) increasing the vacuum chamber pressure to atmospheric pressure; and  
       (g) recovering a coated substrate product having an abrasion resistance greater than or about equal to the abrasion resistance of glass lenses.  
     
     
       23. The method of claim  22  wherein said precursor gases also contain nitrogen and said optically transparent coating material also contains nitrogen. 
     
     
       24. The method of claim  22  wherein a portion of said precursor gases are introduced into the plasma chamber of the ion source, and the remaining portion of said precursor gases are introduced outside of the ion source plasma chamber and into the ion beam. 
     
     
       25. The method of claim  22  wherein said substrate comprises a material selected from the group consisting of a plastic, a metal, a glass and a ceramic. 
     
     
       26. The method of claim  22  wherein said precursor gases for said interlayer comprise materials selected from the group consisting of siloxanes, silanes, silazanes, and mixtures thereof. 
     
     
       27. The method of claim  22  wherein said precursor gases for said interlayer comprise materials selected from the group consisting of hexamethyldisiloxane, tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane and mixtures thereof. 
     
     
       28. A method of producing an optically transparent coating on the surface of a substrate comprising: 
       (a) chemically cleaning the surface of said substrate to remove residual hydrocarbons and other contaminants;  
       (b) mounting said substrate in a deposition vacuum chamber and evacuating the air from said chamber;  
       (c) sputter-etching the surface of said substrate with a beam of gas ions to further remove residual hydrocarbons and other surface contaminants, and to activate the surface;  
       (d) plasma ion beam depositing using a precursor gas a layer of coating material using an ion beam generated in a gridless ion source having a hollow cathode electron source wherein oxygen is introduced into a plasma chamber of said plasma ion source and octamethylcyclotetrasiloxane is injected outside the ion source and directly into the plasma ion beam;  
       (e) increasing the vacuum chamber pressure to atmospheric pressure; and  
       (f) recovering a coated substance product with an abrasion resistance greater than or about equal to the abrasion resistance of glass lenses.  
     
     
       29. A method for producing a diamond- like carbon  ( DLC )  coating on the surface of a substrate using an End Hall ion source comprising:    
       ( a )  chemically cleaning the surface of said substrate to remove residual hydrocarbons and other contaminants;    
       ( b )  mounting said substrate in a deposition vacuum chamber and evacuating the air from said chamber;    
       ( c )  sputter - etching the surface of said substrate with a beam of energetic gas ions to further remove residual hydrocarbons and other surface contaminants, and to activate the surface;    
       ( d )  generating a plasma in a plasma chamber of said End Hall ion source and introducing a hydrocarbon precursor gas into said plasma chamber to form a hydrocarbon - containing plasma ion beam;    
       ( e )  controlling an anode voltage energy of said End Hall ion source and plasma ion beam depositing onto said substrate the DLC coating using said plasma ion beam formed in said End Hall ion source;    
       ( f )  increasing the vacuum chamber pressure to atmospheric pressure; and    
       ( g )  recovering the DLC coated substrate.   
     
     
       30. The method of claim  29  wherein said substrate is a plastic material. 
     
     
       31. The method of claim  29  wherein said substrate is silicon or germanium. 
     
     
       32. The method of claim  29  wherein said precursor gas for said DLC coating is methane. 
     
     
       33. The method of claim  29  wherein said precursor gas for said DLC coating is cyclohexane. 
     
     
       34. The method of claim  29  wherein a rate of deposition of the DLC coating is at least about  176  Å per minute and wherein said hydrocarbon precursor gas is selected from the group consisting of methane, acetylene, acetylene, butane, benzene and mixtures thereof.