Toroidal Plasma Processing Apparatus

Abstract

A plasma processing apparatus including a vacuum chamber comprising a conduit, a process chamber, and a first gas input port for introducing gas into the vacuum chamber, and a pump port for evacuating gas from the vacuum chamber. A magnetic core surrounds the conduit. An output of an RF power supply is electrically connected to the magnetic core. The RF power supply energizes the magnetic core, thereby forming a toroidal plasma loop discharge in the vacuum chamber. A platen that supports a workpiece during plasma processing is positioned in the process chamber.

What is claimed is: 
     
         1 . A plasma processing apparatus comprising:
 a) a vacuum chamber comprising a conduit, a process chamber, and a first gas input port for introducing gas into the vacuum chamber, and a pump port for evacuating gas from the vacuum chamber;   b) a magnetic core surrounding the conduit;   c) an RF power supply having an output that is electrically connected to the magnetic core, the RF power supply energizing the magnetic core, thereby forming a toroidal plasma loop discharge in the vacuum chamber; and   d) a platen that supports a workpiece during plasma processing that is positioned in the process chamber.   
     
     
         2 . The plasma processing apparatus of  claim 1  wherein the vacuum chamber comprises insulating material. 
     
     
         3 . The plasma processing apparatus of  claim 1  wherein the vacuum chamber comprises conductive material. 
     
     
         4 . The plasma processing apparatus of  claim 1  wherein a cross-sectional area of the process chamber is larger than a cross sectional area of the conduit. 
     
     
         5 . The plasma processing apparatus of  claim 1  further comprising a second gas input port positioned proximate to the workpiece. 
     
     
         6 . The plasma processing apparatus of  claim 1  further comprising a second pump port. 
     
     
         7 . The plasma processing apparatus of  claim 1  wherein the conduit has a cross-sectional area that changes proximate to the process chamber. 
     
     
         8 . The plasma processing apparatus of  claim 1  wherein the conduit comprises a dielectric material chosen from a group consisting of fused silica, aluminum oxide, aluminum nitride, composite material, and sapphire. 
     
     
         9 . The plasma processing apparatus of  claim 1  wherein the conduit comprises a conductive material chosen from a group consisting of aluminum, steel, copper, nickel, tungsten, molybdenum, and alloys of aluminum, steel, copper, nickel, tungsten, and molybdenum 
     
     
         10 . The plasma processing apparatus of  claim 1  wherein an inside surface of the process chamber comprises an electrically insulating coating that inhibits at least one of electrical arcing, erosion, and process contamination. 
     
     
         11 . The plasma processing apparatus of  claim 1  wherein the conduit is mounted with an insulating collar that prevents electrical shorting to the chamber to which they are connected. 
     
     
         12 . The plasma processing apparatus of  claim 1  wherein the conduit comprises internal fluid cooling channels. 
     
     
         13 . The plasma processing apparatus of  claim 1  wherein a frequency of signals generated by the RF power supply is in the range of 20 KHz to 14 MHz. 
     
     
         14 . The plasma processing apparatus of  claim 1  wherein the vacuum chamber comprises fluid cooling channels. 
     
     
         15 . The plasma processing apparatus of  claim 1  wherein the platen translates the workpiece relative to the plasma loop. 
     
     
         16 . The plasma processing apparatus of  claim 1  wherein the platen comprises a moveable web substrate platen. 
     
     
         17 . The plasma processing apparatus of  claim 1  wherein the platen is positioned proximate to the plasma loop. 
     
     
         18 . The plasma processing apparatus of  claim 1  wherein the platen is positioned to be displaced from the plasma loop. 
     
     
         19 . The plasma processing apparatus of  claim 1  wherein the platen is positioned to be between 0.1 cm and 5 cm from the center of the plasma loop. 
     
     
         20 . The plasma processing apparatus of  claim 1  wherein the platen comprises internal fluid cooling channels. 
     
     
         21 . The plasma processing apparatus of  claim 1  wherein the vacuum chamber comprises a second conduit. 
     
     
         22 . A plasma processing apparatus comprising:
 a) a vacuum chamber comprising a first and second conduit, a process chamber, and a first gas input port for introducing process gas into the vacuum chamber;   b) a magnetic core surrounding one of the first and second conduit;   c) an RF power supply having an output that is electrically connected to the magnetic core, the RF power supply energizing the magnetic core, thereby forming a toroidal plasma loop discharge in the vacuum chamber; and   d) a platen that supports at least one workpiece that is positioned in the process chamber, the platen having a first section exposed to reactive species from a first section of the plasma loop and a second section exposed to reactive species from a second section of the plasma loop.   
     
     
         23 . The plasma processing apparatus of  claim 22  further comprising a second platen being exposed to reactive species from a section of the plasma loop. 
     
     
         24 . The plasma processing apparatus of  claim 22  wherein the platen comprises a moveable web substrate platen. 
     
     
         25 . The plasma processing apparatus of  claim 22  further comprising a second gas input port positioned proximate to the first section of the plasma loop and a third gas input port positioned proximate to the second section of the plasma loop. 
     
     
         26 . The plasma processing apparatus of  claim 22  wherein at least one of the first and second conduit has a cross-sectional area that changes proximate to the process chamber. 
     
     
         27 . The plasma processing apparatus of  claim 22  further comprising a second process chamber. 
     
     
         28 . The plasma processing apparatus of  claim 22  further comprising a second magnetic core surrounding the other of the first and second conduit, the second magnetic core being electrically connected to an RF power supply having an output that is electrically connected to an RF power supply that energizes the second magnetic core to assist in forming the toroidal plasma loop discharge in the vacuum chamber. 
     
     
         29 . The plasma processing apparatus of  claim 28  wherein the RF power supply electrically connected to the second magnetic core is the same as the RF power supply electrically connected to the first magnetic core. 
     
     
         30 . A method of plasma processing comprising:
 a) forming a vacuum chamber comprising a first and a second conduit, and a process chamber;   b) introducing a first gas into the vacuum chamber at a first gas input port;   c) applying an RF electromagnetic field to a magnetic core positioned around at least one of the first and second conduits to form a toroidal plasma loop discharge in the vacuum chamber;   d) positioning a workpiece in the process chamber for plasma processing; and   e) introducing a process gas proximate to the workpiece at a second gas input port.   
     
     
         31 . The method of  claim 30  wherein the method comprises a method of depositing diamond-containing films. 
     
     
         32 . The method of  claim 30  wherein the method comprises a method of depositing graphene-containing films. 
     
     
         33 . The method of  claim 30  wherein the process gas comprises hydrogen and the toroidal plasma loop discharge generates atomic hydrogen. 
     
     
         34 . The method of  claim 30  wherein a partial pressure of the process gas is at least 1 Torr. 
     
     
         35 . The method of  claim 30  wherein an absorbed RF power is greater than about 10 W cm 3 . 
     
     
         36 . The method of  claim 30  wherein the first gas comprises argon gas and the process gas comprises hydrogen gas. 
     
     
         37 . The method of  claim 30  wherein a partial pressure of the process gases in the process chamber proximate to the workpiece is in the range of 1 Torr to 100 Torr. 
     
     
         38 . The method of  claim 30  wherein the power density in the plasma is at least 100 W cm −3 . 
     
     
         39 . The method of  claim 30  further comprising translating the workpiece relative to the plasma to improve uniformity of the plasma processing. 
     
     
         40 . The method of  claim 30  further comprising rotating the workpiece relative to the plasma to improving uniformity of the plasma processing. 
     
     
         41 . The method of  claim 30  further comprising controlling a temperature at a surface of the workpiece. 
     
     
         42 . The method of  claim 41  wherein the controlling the temperature comprises controlling a temperature of the platen. 
     
     
         43 . The method of  claim 41  wherein the controlling the temperature comprises adjusting a position of the platen relative to the plasma loop. 
     
     
         44 . The method of  claim 41  wherein the controlling the temperature comprises adjusting a pressure of the gas between the platen and workpiece. 
     
     
         45 . The method of  claim 41  further comprising electrically biasing the platen to change a shape of the plasma proximate to the workpiece. 
     
     
         46 . The method of  claim 30  further comprising adjustable gas flow between the process chamber and the conduit. 
     
     
         47 . The method of  claim 30  wherein the process gas comprises carbon. 
     
     
         48 . The method of  claim 30  wherein the process gas comprises hydrogen. 
     
     
         49 . The method of  claim 30  further comprising measuring a temperature of the workpiece and adjusting RF power of the RF electromagnetic field in response to the measurement. 
     
     
         50 . The method of  claim 30  wherein a pressure inside at least one of the first and second conduit is different from a pressure inside the process chamber. 
     
     
         51 . The method of  claim 30  wherein the process gas comprises hydrogen and recombination of atomic hydrogen on the surface of the workpiece heats the workpiece to a desired temperature. 
     
     
         52 . A downstream plasma processing apparatus comprising:
 a) a vacuum chamber comprising a conduit, a reaction chamber, and a first gas input port in a first location for introducing an inert gas into the vacuum chamber and a second gas input port for introducing a process gas in a second location, and an outlet for passing reactive species generated in the reaction chamber, wherein at least one of pressure and concentration of reactive gas in the process chamber being different from at least one of the pressure and concentration in the conduit; a magnetic core surrounding the conduit; and   b) an RF power supply having an output that is electrically connected to the magnetic core, the RF power supply energizing the magnetic core, thereby forming a toroidal plasma loop discharge in the vacuum chamber that generates reactive species for downstream processing.