Gasless ion plating

Abstract

A gasless ion plating process wherein plating material is melted, vaporized, and then subjected to an ionization environment in a low pressure chamber with a "virtual cathode" consisting of a plasma of ionized atoms of evaporant material created by evaporating in an RF field. It is a gasless ion plating process wherein the system ambient pressure prior to plating material evaporation may be much lower than that required to sustain a glow discharge, however, with vapor pressure of evaporant material added to the environment base pressure being such as to result in a plasma of ionized atoms of the plating material developing as the vaporized material approaches the RF cathode.

I claim: 
     
       1. A process for ion plating a substrate supported within a chamber with a plating material and in the absence of any inert gas inputted to said chamber, comprising the steps of: evacuating said chamber, vaporizing plating material in the evacuated chamber, developing a direct current negative bias on said substrate, and applying a radio frequency field from a .[.first.]. radio frequency source to the vaporized plating material within said chamber. 
     
     
       2. The ion plating process of claim 1, wherein said substrate is conductive, and said step of developing a direct current negative bias on said substrate comprises the application of a direct current negative bias source to said substrate.  .[.3. The ion plating process of claim 2, further including the application of a further radio frequency signal 
     
     
        source to said substrate..]. 4. The process of claim .[.3.]. .Iadd.1 .Iaddend.wherein said radio frequency field applied within said chamber is at a frequency within the range of approximately .[.10 to 800 kilohertz, and said further radio frequency signal applied to the substrate is in the 
     
     
        range of approximately.]. 2 to 40 megahertz. 5. The process of claim 1, wherein the substrate is to be cleaned prior to plating, further comprising the preliminary steps of: evacuating said chamber; introducing an inert gas into said chamber; and applying a radio frequency field to an 
     
     
        area within said chamber. 6. The process of claim 1, wherein the step of vaporizing is a result of the step of applying the radio frequency field. 
     
     
         . A process for plating a substrate supported within a chamber with a plating material comprising the steps of: evacuating said chamber; vaporizing said plating material in the evacuated chamber; developing a direct current negative bias on said substrate; forming and maintaining an ionized plasma from the vaporized plating material in the absence of any inert gas inputted to said chamber; and applying a radio frequency field within said chamber to ion plate said material from said plasma onto said substrate.  .[.8. The process of claim 7, wherein the steps of vaporizing plating material, forming an ionized plasma, and applying a radio frequency field, are performed concurrently from a single radio frequency power supply..]. .[.9. Apparatus for plating a conductive substrate with a plating material, including: a chamber adapted to hold said substrate and said plating material; means for evacuating said chamber; means for vaporizing said plating material in the evacuated chamber; means for applying radio frequency power to the vaporized plating material to form and maintain an ionized plasma therefrom in the absence of any inert gas inputted to said chamber; a radio frequency bias source means connected to said substrate; and means for applying a direct current negative bias to said substrate..]. .[.10. The apparatus of claim 9, further including connection of said radio frequency bias source means through a radio frequency coupling capacitive means to said substrate..]. .[.11. The apparatus of claim 10, wherein said means for applying a direct current negative bias to said substrate includes a direct current source having a negative terminal connection through RF choke means to said substrate and a positive terminal connection to a voltage potential reference source of the system..]. .[.12. The apparatus of claim 9, wherein said radio frequency power is at a frequency of about 450 kilohertz, and including means for applying a further radio frequency bias source means at a frequency of about 13.5 megahertz to said substrate..]. .[.13. The apparatus of claim 9, wherein the vaporizing means is a conventional resistance heat element device..]. .[.14. The apparatus of claim 13, wherein said vaporizing means is a filament device..]. .[.15. The apparatus of claim 13, wherein said vaporizing means is a boat..]. .Iadd. 16. A process for ion plating a substrate within a chamber with a plating material source inside of said chamber comprising the steps of evacuating said chamber, vaporizing said plating material, effecting a D.C. negative electrical potential to the substrate relative to the source of plating material and other portions of the chamber by applying a D.C. bias to the substrate, applying an RF signal to the substrate creating an RF field at the substrate wherein the RF field creates an ionized plasma from the vaporized plating material in the immediate vicinity of the substrate with the ionized plating material thus accelerated onto the substrate surface as a result of the negative electrical potential, for particular advantage in plating a conductive substrate. .Iaddend..Iadd. 17. Apparatus for plating a substrate with a plating material including a chamber adapted to hold said substrate and said plating material, means for evacuating said chamber, means for vaporizing said plating material in the evacuated chamber, RF source means connected within the chamber to apply radio frequency signal power at said substrate creating an RF field at said substrate, said RF field creating means to ionize the plating material forming a plasma substantially surrounding the substrate, and external source means for inducing a D.C. negative bias on the substrate relative to the rest of the chamber. .Iaddend..Iadd. 18. The apparatus of claim 17, particularly adapted to plate a conductive substrate wherein the means for inducing a D.C. negative bias on the substrate includes a D.C. bias source connected to the substrate. .Iaddend. .Iadd. 19. The apparatus of claim 17, wherein the means for vaporizing the plating material comprises a further RF source means which operates at a frequency of about 450 kilohertz. .Iaddend..Iadd. 20. The apparatus of claim 17, wherein the means for vaporizing the plating material is a resistance heat element device. .Iaddend..Iadd. 21. The apparatus of claim 20, wherein the means for vaporizing the plating material is a filament device. .Iaddend..Iadd. 22. The apparatus of claim 20, wherein the means for vaporizing the plating material is a boat device. .Iaddend..Iadd. 23. The apparatus of claim 17, including the connection of said RF source means through a radio frequency coupling capacitive means to said substrate. .Iaddend..Iadd. 24. The apparatus of claim 23, wherein said means for creating a DC negative potential to the substrate includes a direct current source having a negative terminal connection through RF choke means to said substrate and a positive terminal connection to a voltage potential reference source of the system. .Iaddend. .Iadd. 25. A process for ion plating a substrate supported within a chamber with a plating material comprising the steps of: evacuating said chamber; vaporizing plating material in the evacuated chamber at a pressure prior to evaporation lower than necessary to sustain a glow discharge, effecting a DC negative bias on said substrate, and applying a radio frequency field at the substrate to the vaporized plating material immediately adjacent the substrate within said chamber. .Iaddend. .Iadd. 26. A process for plating a substrate supported within a chamber with a plating material comprising the steps of: evacuating said chamber, vaporizing said plating material in the evacuated chamber, developing a DC negative bias on said substrate, forming and maintaining an ionized plasma from the vaporized plating material in the absence of any inert gas inputted to said chamber; and applying a radio frequency field within said chamber to ion plate said material from said plasma onto said substrate. .Iaddend. .Iadd. 27. The process of claim 26, wherein the system ambient pressure prior to the plating material evaporation is lower than that necessary to sustain a glow discharge. .Iaddend. .Iadd. 28. Apparatus for plating a substrate with a plating material, including: a chamber adapted to hold said substrate and said plating material; means for evacuating said chamber; means for vaporizing said plating material in the evacuated chamber; means for applying radio frequency power to the vaporized plating material to form and maintain an ionized plasma therefrom in the absence of any inert gas inputted to said chamber; a radio frequency bias source means adapted to be connected to said substrate; and means for applying a DC negative bias to said substrate. .Iaddend.