Method and apparatus for generating highly repetitive pulsed plasmas

Abstract

A pulsed radio frequency inductive plasma source and method are provided. The source may generate plasma at gas pressures from 1 torr to 2000 torr. By utilizing high power RF generation from fast solid state switches such as Insulated-Gate Bipolar Transistor (IGBT) combined with the resonance circuit, large inductive voltages can be applied to RF antennas to allow rapid gas breakdown from 1-100 μs. After initial breakdown, the same set of switches or an additional rf pulsed power systems are utilized to deliver large amount of rf power, between 10 kW to 10 MW, to the plasmas during the pulse duration of 10 μs-10 ms. In addition, several methods and apparatus for controlling the pulse power delivery, timing gas and materials supply, constructing reactor and substrate structure, and operating pumping system and plasma activated reactive materials delivery system will be disclosed. When combined with the pulsed plasma generation, these apparatuses and the methods can greatly improve the applicability and the efficacy of the industrial plasma processing.

1 . An apparatus of generating plasma, comprising:
 a pulsed radio frequency source that is driven with a pulse duration and generates a pulsed radio frequency signal;   a reactor chamber that contains a carrier gas and one or more reactive precursors with a pressure of between 1 torr and 2,000 torr;   an inductive antenna, coupled to the pulsed radio frequency source, that surrounds a portion of the reactor chamber; and   wherein the pulsed radio frequency signal is delivered to the inductive antenna that initiates a breakdown of the carrier gas and one or more reactive precursors and generates a plasma due to the breakdown of the carrier gas and one or more reactive precursors.   
     
     
         2 . The apparatus of  claim 1 , wherein the pulse duration is greater than 10 μs. 
     
     
         3 . The apparatus of  claim 1 , wherein the pulse duration is less than 10 ms. 
     
     
         4 . The apparatus of  claim 1 , wherein the pulse duration is between 10 μs and 10 ms. 
     
     
         5 . The apparatus of  claim 1 , wherein the radio frequency is greater than 50 kHz. 
     
     
         6 . The apparatus of  claim 1 , wherein the radio frequency is less than 10 MHz. 
     
     
         7 . The apparatus of  claim 1 , wherein the inductive antenna is a cylindrical coil of a single turn or multi-turns. 
     
     
         8 . The apparatus of  claim 1 , wherein the pulsed radio frequency source changes its frequency after initiation of the plasma. 
     
     
         9 . The apparatus of  claim 1  further comprising a second pulsed radio frequency source that is driven with a pulse duration and generates a second pulsed radio frequency signal and a second inductive antenna, coupled to the second pulsed radio frequency source, that surrounds the portion of the reactor chamber, wherein the second pulsed radio frequency signal sustains the plasma. 
     
     
         10 . The apparatus of  claim 1  further comprising an inlet system to provide the carrier gases and the one or more reactive precursors into the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 100%. 
     
     
         11 . The apparatus of  claim 1  further comprising a pumping system to maintain the pressure in the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 100%. 
     
     
         12 . The apparatus of  claim 1 , wherein the pulsed radio frequency source has a repetition rate from 1 Hz to 1 kHz. 
     
     
         13 . The apparatus of  claim 12 , wherein the repetitively pulsed radio frequency source operates at a duty factor from 0.1% and 20%. 
     
     
         14 . The apparatus of  claim 1  further comprising a material collection system to collect materials formed in the reactor chamber. 
     
     
         15 . The apparatus of  claim 1  further comprising a substrate component with target materials to be treated by the one or more reactive precursors that are activated by the plasma. 
     
     
         16 . The apparatus of  claim 15 , wherein the substrate component is one of at an output of the reactor chamber and within the reactor chamber. 
     
     
         17 . The apparatus of  claim 15 , wherein the substrate component is located on the moveable stage where it is continuously transported from outside the reactor chamber into the reactor chamber to be treated by the one or more reactive precursors that are activated by the plasma and is moved out of the reactor chamber upon completion of the treatment. 
     
     
         18 . The apparatus of  claim 1 , wherein the rf power to the plasma is more than 10 kW during the pulse. 
     
     
         19 . The apparatus of  claim 1 , wherein the rf power to the plasma is less than 10 MW during the pulse. 
     
     
         20 . The apparatus of  claim 18 , wherein one or more reactive precursor materials are in one of a gaseous phase, a liquid phase or a solid phase. 
     
     
         21 . The apparatus of  claim 20 , wherein the one or more reactive precursor materials are complex compound materials including copper indium gallium selenide and YAG. 
     
     
         22 . The apparatus of  claim 20 , wherein the linear size of the solid precursor materials is less than 0.1 mm. 
     
     
         23 . The apparatus of  claim 20 , wherein the linear size of the solid precursor materials is more than 10 nm. 
     
     
         24 . The apparatus of  claim 20 , wherein the linear size of the liquid precursor materials is less than 0.1 mm. 
     
     
         25 . The apparatus of  claim 20 , wherein the linear size of the liquid precursor materials is more than 10 nm. 
     
     
         26 . The apparatus of  claim 20 , wherein one or more reactive precursor materials are reactive gases containing hydrogen, oxygen, nitrogen, fluorine, chlorine, sulfur, phosphor and hydrocarbon. 
     
     
         27 . The apparatus of  claim 20 , wherein one or more reactive precursor materials are acids, bases, polymers, metals, ceramics, and composite materials. 
     
     
         28 . The apparatus of generating plasma, comprising:
 a pulsed radio frequency source that is driven with a pulse duration and generates a pulsed radio frequency signal;   a reactor chamber that contains a carrier gas and one or more reactive precursors with a pressure of between 1 torr and 2000 torr;   an inductive antenna, coupled to the pulsed radio frequency source, that surrounds a portion of the reactor chamber;   a material exhaust system, connected to the reactor chamber, that regulate the materials flow out of the reactor; and   wherein the pulsed radio frequency signal is delivered to the inductive antenna that initiates a breakdown of the carrier gas and one or more reactive precursors and generates a plasma due to the breakdown of the carrier gas and one or more reactive precursors and activate one or more reactive precursors by the plasma and exhaust the material flow from one or more reactive precursors that are activated by the plasma out of the reactor.   
     
     
         29 . The apparatus of  claim 28  further comprising a pulsed material exhaust system to allow the flow of one or more reactive precursors that are activated by the plasma out of the reactor in a repetitively pulsed manner with the duty factor between 1% and 99% and with the repetition frequency between 1 Hz and 100 Hz. 
     
     
         30 . The apparatus of  claim 28  further comprising a pumping system to maintain the pressure in the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 99%. 
     
     
         31 . The apparatus of  claim 28  further comprising an inlet system to provide the carrier gases into the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 99%. 
     
     
         32 . The apparatus of  claim 28  further comprising an inlet system to provide one or more reactive precursors into the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 99%; 
     
     
         33 . The apparatus of  claim 28  further comprising a nozzle to direct the flow of one or more reactive precursors that are activated by the plasma onto the target surfaces located outside the reactor in an ambient pressure to be treated by the one or more reactive precursors that are activated by the plasma. 
     
     
         34 . The apparatus of  claim 28  further comprising thermally sensitive target materials and materials for plasma assisted material deposition and coating, surface removal, surface activation and surface property modification. 
     
     
         35 . A method for generating plasma in a reactor chamber that contains a carrier gas and one or more reactive precursors with a pressure of between 1 torr and 2,000 torr, the method comprising:
 generating, by a pulsed radio frequency source that is driven with a pulse duration, a pulsed radio frequency signal;   delivering the pulsed radio frequency signal to an inductive antenna coupled to the pulsed radio frequency source and surrounding a portion of the reactor chamber; and   initiating, by the pulsed radio frequency signal delivered to the inductive antenna, in the reactor chamber a breakdown of the carrier gas and one or more reactive precursors to generate a plasma.   
     
     
         36 . The method of  claim 35 , wherein generating the pulsed radio frequency signal further comprises generating the pulsed radio frequency signal with a pulse duration that is greater than 10 μs. 
     
     
         37 . The method of  claim 35 , wherein generating the pulsed radio frequency signal further comprises generating the pulsed radio frequency signal with a pulse duration that is less than 10 ms. 
     
     
         38 . The method of  claim 35 , wherein generating the pulsed radio frequency signal further comprises generating the pulsed radio frequency signal with a pulse duration that is between 10 μs and 10 ms. 
     
     
         39 . The method of  claim 35  further comprising changing, by the pulsed radio frequency source, its frequency after initiation of the plasma. 
     
     
         40 . The method of  claim 35  further comprising generating, by a second pulsed radio frequency source, a second pulsed radio frequency signal and sustaining, by an inductive antenna coupled to the second pulsed radio frequency source, the plasma by the second pulsed radio frequency signal. 
     
     
         41 . The method of  claim 35  further comprising providing, by an inlet system, the carrier gases and the one or more reactive precursors into the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 100%. 
     
     
         42 . The method of  claim 35  further comprising maintaining, by a pumping system, a pressure in the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 100%. 
     
     
         43 . The method of  claim 35  further comprising collecting, by a material collection system, materials formed in the reactor chamber. 
     
     
         44 . The method of  claim 34  further comprising treating target materials using the one or more reactive precursors that are activated by the plasma. 
     
     
         45 . The method of  claim 44 , wherein one or more reactive precursor materials are in one of a gaseous phase, a liquid phase or a solid phase. 
     
     
         46 . The method of  claim 44 , wherein one or more reactive precursor materials is one of a reactive gas containing hydrogen, oxygen, nitrogen, fluorine, chlorine, sulfur, phosphor and hydrocarbon. 
     
     
         47 . The method of  claim 44 , wherein one or more reactive precursor materials are acids, bases, polymers, metals, ceramics, and composite materials. 
     
     
         48 . A method for generating plasma in a reactor chamber that contains a carrier gas and one or more reactive precursors with a pressure of between 1 torr and 2,000 torr, the method comprising:
 generating, by a pulsed radio frequency source that is driven with a pulse duration, a pulsed radio frequency signal;   delivering the pulsed radio frequency signal to an inductive antenna coupled to the pulsed radio frequency source and surrounding a portion of the reactor chamber;   initiating, by the pulsed radio frequency signal delivered to the inductive antenna, in the reactor chamber a breakdown of the carrier gas and one or more reactive precursors to generate a plasma that activates the one or more reactive precursors; and   exhausting, by a material exhaust system connected to the reactor chamber, the material flow from one or more activated reactive precursors out of the reactor chamber.   
     
     
         49 . The method of  claim 48 , wherein exhausting the material flow further comprises exhausting the material flow from one or more activated reactive precursors out of the reactor chamber in a repetitively pulsed manner with a duty factor between 1% and 99% and with a repetition frequency between 1 Hz and 100 Hz. 
     
     
         50 . The method of  claim 48  further comprising maintaining, by a pumping system, a pressure in the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 100%. 
     
     
         51 . The method of  claim 48  further comprising providing, by an inlet system, the carrier gases and the one or more reactive precursors into the reactor chamber in a repetitively pulsed manner with the duty factor between 1% and 100%. 
     
     
         52 . The method of  claim 48  further comprising directing, using a nozzle, a flow of one or more reactive precursors onto a target surface located outside the reactor chamber in an ambient pressure so that the target surface and the one or more reactive precursors are activated by the plasma when the target surface is in the reactor chamber.