Method of CVD Plasma Processing with a Toroidal Plasma Processing Apparatus

Abstract

A method of CVD plasma processing for depositing at least one of diamond, diamond-like-carbon, or graphene comprising includes forming a vacuum chamber comprising a first toroidal plasma source comprising a conduit and a magnetic core, a second toroidal plasma source comprising a conduit and a magnetic core, and a process chamber that is common to both the first and second toroidal plasma source. Gas is introduced into the vacuum chamber. A first RF electromagnetic field is applied to the magnetic core surrounding the conduit of the first toroidal plasma source to form a first toroidal plasma loop discharge in the vacuum chamber. A second RF electromagnetic field is applied to the magnetic core surrounding the conduit of the second toroidal plasma source to form a second toroidal plasma loop discharge in the vacuum chamber. A workpiece is positioned in the process chamber for plasma processing at a distance from a hot plasma core to a surface of the workpiece that is in a range from 0.1 cm to 5 cm. A gas comprising hydrogen is introduced to the workpiece so that at least one of the first and second toroidal plasma loop discharges generates atomic hydrogen.

1 - 29 . (canceled) 
     
     
         30 . A method of CVD plasma processing for depositing at least one of diamond, diamond-like-carbon, or graphene, the method comprising:
 a) forming a vacuum chamber comprising a first toroidal plasma source comprising a conduit and a magnetic core, a second toroidal plasma source comprising a conduit and a magnetic core, and a process chamber that is common to both the first and second toroidal plasma source;   b) introducing a gas into the vacuum chamber;   c) applying a first RF electromagnetic field to the magnetic core surrounding the conduit of the first toroidal plasma source to form a first toroidal plasma loop discharge in the vacuum chamber;   d) applying a second RF electromagnetic field to the magnetic core surrounding the conduit of the second toroidal plasma source to form a second toroidal plasma loop discharge in the vacuum chamber;   e) positioning a workpiece in the process chamber for plasma processing at a distance from a hot plasma core to a surface of the workpiece that is in a range from 0.1 cm to 5 cm; and   f) introducing a gas comprising hydrogen to the workpiece so that at least one of the first and second toroidal plasma loop discharges generates atomic hydrogen.   
     
     
         31 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber comprises forming the first toroidal plasma with a pair of conduits. 
     
     
         32 . The method of CVD plasma processing of  claim 31  further comprising positioning a separate magnetic core around each conduit in the pair of conduits. 
     
     
         33 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber comprising the second toroidal plasma source comprising the conduit and the magnetic core comprises forming the second toroidal plasma with a pair of conduits. 
     
     
         34 . The method of CVD plasma processing of  claim 33  further comprising positioning a separate magnetic core around each conduit in the pair of conduits. 
     
     
         35 . The method of CVD plasma processing of  claim 30  further comprising stacking the first and the second plasma source across the width of the workpiece. 
     
     
         36 . The method of CVD plasma processing of  claim 30  further comprising stacking the first and the second toroidal plasma sources across the length of the workpiece. 
     
     
         37 . The method of CVD plasma processing of  claim 30  further comprising positioning the first and second toroidal plasma sources so that the first and the second toroidal plasma loop discharges overlap in the vacuum chamber to control uniformity of the CVD plasma processing. 
     
     
         38 . The method of CVD plasma processing of  claim 30  further comprising positioning the first and second toroidal plasma sources so that the first and the second toroidal plasma loop discharges are offset in the vacuum chamber to control uniformity of the CVD plasma processing. 
     
     
         39 . The method of CVD plasma processing of  claim 30  further comprising translating the workpiece in order to control the uniformity of the CVD plasma processing. 
     
     
         40 . The method of CVD plasma processing of  claim 30  further comprising translating the workpiece in order to control the rate of the CVD plasma processing. 
     
     
         41 . The method of CVD plasma processing of  claim 30  wherein the gas comprises argon gas. 
     
     
         42 . The method of CVD plasma processing of  claim 30  wherein the introducing the gas comprising hydrogen to the workpiece achieves a pressure of hydrogen that is in the range of 1 Torr to 200 Torr. 
     
     
         43 . The method of CVD plasma processing of  claim 30  further comprising controlling a temperature at the surface of the workpiece by adjusting a pressure of the gas comprising hydrogen introduced to the workpiece. 
     
     
         44 . The method of CVD plasma processing of  claim 30  wherein the applying the first RF electromagnetic field to the magnetic core surrounding the conduit of the first toroidal plasma source comprises coupling an RF electromagnetic field so that the power density of the first toroidal plasma loop discharge is at least 100 W cm −3  at a distance from the hot plasma core to the surface of the workpiece is in the range 0.1 cm to 5 cm. 
     
     
         45 . The method of CVD plasma processing of  claim 30  wherein the applying the second RF electromagnetic field to the magnetic core surrounding the conduit of the second toroidal plasma source comprises coupling an RF electromagnetic field so that the power density of the second toroidal plasma loop discharge is at least 100 W cm −3  at a distance from the hot plasma core to the surface of the workpiece that is in the range 0.1 cm to 5 cm. 
     
     
         46 . The method of CVD plasma processing of  claim 30  further comprising rotating the workpiece relative to at least one of the first and the second toroidal plasma loop discharges to improve uniformity of the CVD plasma processing. 
     
     
         47 . The method of CVD plasma processing of  claim 30  further comprising controlling a temperature at the surface of the workpiece by controlling a temperature of a platen supporting the workpiece. 
     
     
         48 . The method of CVD plasma processing of  claim 30  further comprising controlling a temperature at the surface of the workpiece by adjusting a position of a platen supporting the workpiece relative to the hot plasma core. 
     
     
         49 . The method of CVD plasma processing of  claim 30  further comprising electrically biasing a platen supporting the workpiece to change a shape of at least one of the first and second toroidal plasma loop discharge proximate to the workpiece. 
     
     
         50 . The method of CVD plasma processing of  claim 30  further comprising adjusting a gas flow between the process chamber and the conduit of at least one of the first and second toroidal plasma source. 
     
     
         51 . The method of CVD plasma processing of  claim 30  further comprising introducing a carbon-containing gas to the workpiece. 
     
     
         52 . The method of CVD plasma processing of  claim 30  further comprising measuring a temperature of the workpiece and adjusting an RF power of the applied RF electromagnetic field to the magnetic core surrounding the conduit of at least one of the first and second toroidal plasma source in response to the measurement. 
     
     
         53 . The method of CVD plasma processing of  claim 30  wherein a partial pressure of hydrogen inside the conduit in the at least one of the first and second toroidal plasma sources is different from a partial pressure of hydrogen inside the process chamber. 
     
     
         54 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber further comprises forming the process chamber with a cross-sectional area that is greater than a cross-sectional area of the conduit in the at least one of the first and second toroidal plasma sources. 
     
     
         55 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber further comprises forming the conduit from a dielectric material chosen from a group consisting of fused silica, aluminum oxide, aluminum nitride, composite material, and sapphire, wherein the conduit and the process chamber can be formed of the same or from a different material. 
     
     
         56 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber further comprises forming the conduit from a conductive material chosen from a group consisting of aluminum, steel, copper, tungsten, molybdenum, and alloys of aluminum, steel, copper, nickel, tungsten, and molybdenum, wherein the conduit and the process chamber can be formed of the same or from a different material. 
     
     
         57 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber further comprises forming the conduit in the at least one of the first and second toroidal plasma sources with a cross-sectional area that changes proximate to the process chamber. 
     
     
         58 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber further comprises forming the process chamber with an inside surface that is coated by an electrically insulating material. 
     
     
         59 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber further comprises forming the process chamber with an inside surface comprising a metal selected from the group consisting of aluminum, anodized aluminum, stainless steel, tungsten, and molybdenum. 
     
     
         60 . The method of CVD plasma processing of  claim 30  wherein the forming the vacuum chamber further comprises mounting the conduit in the at least one of the first and second toroidal plasma sources with an insulating collar that is arranged to prevent electrical shorting to the process chamber. 
     
     
         61 . The method of CVD plasma processing of  claim 30  wherein the applying the first RF electromagnetic field to the magnetic core surrounding the conduit in the first toroidal plasma source comprises applying RF electromagnetic signals with a frequency that is in a range of 20 KHz to 14 MHz. 
     
     
         62 . The method of CVD plasma processing of  claim 30  wherein the applying the second RF electromagnetic field to the magnetic core surrounding the conduit in the second toroidal plasma source comprises applying RF electromagnetic signals with a frequency that is in a range of 20 KHz to 14 MHz. 
     
     
         63 . The method of CVD plasma processing of  claim 30  wherein the positioning the workpiece in the process chamber further comprises positioning the workpiece so that it is exposed to reactive species in both the first and second toroidal plasma loop discharge. 
     
     
         64 . The method of CVD plasma processing of  claim 30  wherein the gas comprising hydrogen is introduced to the workpiece to achieve a pressure at the workpiece that is over 200 Torr. 
     
     
         65 . The method of CVD plasma processing of  claim 30  wherein the gas comprising hydrogen and the gas are introduced at different gas ports. 
     
     
         66 . The method of CVD plasma processing of  claim 30  wherein the gas comprising hydrogen and the gas are introduced at the same gas input port.