Plasma treatment of processing gases

Abstract

The present invention provides a DBD cell ( 500 ) including ring shaped electrodes ( 512 and 514 ) that are positioned side-by-side on a dielectric tube ( 516 ). An AC power supply ( 518 ) is provided such that the cell and the power supply form a DBD treatment device ( 540 ) for abatement of noxious gases for example FCs that can be discharged from semiconductor fabricating devices. Additionally, one or more sensors ( 822 ) and/or one or more gas addition ports ( 816 ) can be included in a DBD cell ( 800 ) of the present invention. Several DBD cells ( 1030, 1036 and 1042 ) of the present invention can be combined to form a DBD reactor ( 1010 ) of the present invention. AC power supplies ( 1012, 1014 and 1016 ) are utilized to energize the cells ( 1030, 1036 and 1042 ), forming a novel noxious gas treatment device ( 1000 ) wherein plasmas are created when gas is present inside the reactor. A DBD treatment device ( 1314 ) of the present invention can be operably connected to the gas discharge system of a semiconductor fabricating device ( 1310 ), forming a novel semiconductor processing system. Furthermore, DBD devices of the present invention ( 1714 ) can be utilized to form fluorine species for use in chemical processing methods, techniques and devices including wafer fabricating devices ( 1718 ). Additionally, DBD treatment devices of the present invention ( 1540, 1542 and 1544 ) can be integrated with vacuum pump stages ( 1520, 1522, 1524, 1526 and 1528 ) to form a novel pump integrated DBD treatment apparatus ( 1500 ).

We claim:  
     
         1 . A DBD cell comprising: 
 a) a substantially cylindrical dielectric tube having (1) a tube wall and (2) an outside surface;    b) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube;    c) a second electrically conductive electrode positioned on the outside surface of the tube and encircling the tube, wherein (1) the second electrode is positioned a distance D from the first electrode and (2) the first and second electrodes are placed in a side-by-side position, and wherein the cell is adapted for forming a plasma inside the tube through dielectric barrier discharge such that high frequency energy is capacitively discharged through the tube wall.    
     
     
         2 . The cell of  claim 1  wherein the first and second electrodes comprise electrode segments.  
     
     
         3 . The cell of  claim 2  wherein the first and second electrodes each include at least one fastener having a biasing element for urging the segments of each cell together.  
     
     
         4 . The cell of  claim 1  wherein distance D ranges from about 10 mm to about 30 mm.  
     
     
         5 . The cell of  claim 1  wherein the first and second electrodes comprise shapes selected from the group consisting of rings and cylindrical bands.  
     
     
         6 . The cell of  claim 1  wherein the first and second electrodes include heat exchange elements.  
     
     
         7 . The cell of  claim 1  additionally comprising: 
 a) a first electrical contact formation included in the first electrode; and  
 b) a second electrical contact formation included in the second electrode.  
 
     
     
         8 . The cell of  claim 1  additionally comprising: 
 a) a first gap between the first electrode and the tube's outside surface; and  
 b) a second gap between the second electrode and the tube's outside surface.  
 
     
     
         9 . The cell of  claim 8  additionally comprising an electrically insulating paste positioned in the first and second gaps.  
     
     
         10 . The cell of  claim 9  wherein the paste comprises one or more materials selected from the group consisting of silicones, polytetrafluoreoethylene, and mixtures of perfluoropolyethers and polytetrafluoroethylene.  
     
     
         11 . The cell of  claim 1  additionally comprising one or more ports for introducing one or more gases.  
     
     
         12 . The cell of  claim 1  additionally comprising one or more sensors.  
     
     
         13 . The cell of  claim 1  additionally comprising one or more optical windows.  
     
     
         14 . The cell of  claim 1  wherein the tube comprises a material selected from the group consisting of alumina, quartz and sapphire.  
     
     
         15 . The cell of  claim 1  additionally adapted for treating a gas by generating a plasma in the gas.  
     
     
         16 . A DBD reactor comprising: 
 a) a first DBD cell including: (1) a substantially cylindrical dielectric tube having a tube wall and an outside surface, (2) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube, (3) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein (i) the second electrode is positioned a first distance from the first electrode, and (ii) the first and second electrodes are placed in a side-by-side position, and (4) wherein the first cell is adapted for forming a plasma inside the tube through dielectric barrier discharge such that high frequency energy is capacitively discharged through the tube wall; and    c) at least a second DBD cell including: (1) the tube, (2) a third electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (3) a fourth electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein (i) the fourth electrode is positioned a second distance from the first electrode and (ii) the third and fourth electrodes are placed in a side-by-side position, and (4) wherein the second cell is adapted for forming a plasma inside the tube through dielectric barrier discharge such that high frequency energy is capacitively discharged through the tube wall.    
     
     
         17 . A DBD treatment device comprising: 
 a) a first DBD cell including: (1) a substantially cylindrical dielectric tube having an outside surface, (2) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (3) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein (i) the second electrode is positioned a distance D from the first electrode and (ii) the first and second electrodes are placed in a side-by-side position; and    b) an AC power supply electrically connected to the first and second electrodes, such that the power supply is adapted for energizing the cell to form a plasma through dielectric barrier discharge when a gas is present inside the tube.    
     
     
         18 . The device of  claim 17  wherein the AC power supply comprises a switched mode resonant high voltage power supply.  
     
     
         19 . The device of  claim 17  wherein the AC power supply comprises: 
 a) a DC power supply;  
 b) a capacitor in parallel with the DC power supply; and  
 c) electrical components connected in series including: (1) an inductor, (2) a primary winding of a transformer and (3) a MOSFET switch having a snubber capacitor in parallel with the switch and wherein the series is in parallel with the DC power supply.  
 
     
     
         20 . The device of  claim 19  wherein the DC power supply comprises a DC power supply providing a DC voltage input to the components connected in series, wherein the input voltage ranges from 30 V to 48 V.  
     
     
         21 . The device of  claim 19  wherein the DC power supply is a constant power DC power supply.  
     
     
         22 . The device of  claim 19  additionally comprising an electrical circuit including a secondary winding of the transformer, wherein the electrical circuit is adapted for energizing the cell by applying an AC voltage.  
     
     
         23 . The device of  claim 22  wherein the AC voltage has a frequency of about 900 kHz and a peak voltage of about 3 KV.  
     
     
         24 . The device of  claim 17  wherein the distance D ranges from about 10 mm to about 30 mm.  
     
     
         25 . A DBD treatment device comprising: 
 a) a DBD reactor including: (1) a first DBD cell including: (i) a substantially cylindrical dielectric tube having an outside surface, (ii) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (iii) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein the second electrode is positioned a first distance from the first electrode and wherein the first and second electrodes are placed in a side-by-side position, and (2) at least a second DBD cell including: (i) the tube, (ii) a third electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (iii) a fourth electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein the fourth electrode is positioned a second distance from the third electrode and wherein the third and fourth electrodes are placed in a side-by-side position;    b) a first AC power supply electrically connected to the first and second electrodes, such that the first power supply is adapted for energizing the first cell to form a plasma through dielectric barrier discharge when a gas is present in the tube; and    c) a second AC power supply electrically connected to the third and fourth electrodes, such that the second power supply is adapted for energizing the at least second cell to form a plasma through dielectric barrier discharge when a gas is present in the tube.    
     
     
         26 . The treatment device of  claim 25  wherein the first and second AC power supplies are adapted for being controlled independently of each other.  
     
     
         27 . The treatment device of  claim 25  additionally comprising: 
 a) first DC power supply adapted for providing AC power to the first AC power supply;  
 b) and a second power supply adapted for providing DC power to the second AC power supply, wherein the first and second DC power supplies are adapted for being controlled independently of each other.  
 
     
     
         28 . A pump integrated DBD treatment apparatus comprising: 
 a) n vacuum pump stages; and    b) n minus 2 DBD treatment devices integrated with the n vacuum pump stages wherein each of the n minus 2 DBD treatment devices comprises at least one DBD cell including: (1) a substantially cylindrical dielectric tube having an outside surface, (2) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (3) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein (i) the second electrode is positioned a first distance from the first electrode and (ii) the first and second electrodes are placed in a side-by-side position and (4) an AC power supply electrically connected to the first and second electrodes, such that the power supply is adapted for energizing the cell to form a plasma through dielectric barrier discharge when a gas is present inside the tube.    
     
     
         29 . The apparatus of  claim 28  wherein the n vacuum pump stages each comprise a Roots vacuum pump stage.  
     
     
         30 . The apparatus of  claim 28  wherein the AC power supply comprises a switched mode resonant high voltage power supply.  
     
     
         31 . The apparatus of  claim 28  wherein each of the n minus 2 DBD devices is adapted for being energized by an AC power supply that provides an AC frequency that is different from the AC frequencies of the other AC power supplies of the apparatus.  
     
     
         32 . A semiconductor processing system comprising: 
 a) a semiconductor fabricating device;    b) at least one DBD cell including: (1) a substantially cylindrical dielectric tube having a tube wall and an outside surface, (2) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube; (3) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein (i) the second electrode is positioned a distance D from the first electrode and (ii) the first and second electrodes are placed in a side-by-side position, and (4) wherein the at least one DBD cell is adapted for forming a plasma inside the tube through dielectric barrier discharge such that high frequency energy is capacitively discharged through the tube wall; and    c) a gas flow connection between the fabricating device and the tube.    
     
     
         33 . The system of  claim 32  wherein the first and second electrodes comprise shapes selected from the group consisting of rings and cylindrical bands.  
     
     
         34 . The system of  claim 32 , wherein the semiconductor fabricating device comprises an etch chamber.  
     
     
         35 . The system of  claim 32  wherein the DBD cell is adapted for treating one or more gaseous compounds that are discharged from the fabricating device.  
     
     
         36 . The system of  claim 32  wherein the DBD cell is adapted for generating fluorine species for use in the fabricating device.  
     
     
         37 . A semiconductor processing system comprising: 
 a) a semiconductor fabricating device;    b) a DBD treatment device including: (I) a DBD reactor having (1) a first DBD cell including: (i) a substantially cylindrical dielectric tube having an outside surface, (ii) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (iii) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein the second electrode is positioned a first distance from the first electrode and wherein the first and second electrodes are placed in a side-by-side position, and (2) at least a second DBD cell including: (i) the tube, (ii) a third electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (iii) a fourth electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein the fourth electrode is positioned a second distance from the third electrode and wherein the third and fourth electrodes are placed in a side-by-side position, (II) a first AC power supply electrically connected to the first and second electrodes such that the first power supply is adapted for energizing the first cell to form a plasma through dielectric barrier discharge, and (III) a second AC power supply electrically connected to the third and fourth electrodes such that the second power supply is adapted for energizing the second cell to form a plasma through dielectric barrier discharge; and    c) a gas flow connection between the fabricating device and the tube.    
     
     
         38 . The system of  claim 37  additionally comprising: 
 a) a controller; and  
 b) an interlock feature in connection with the controller.  
 
     
     
         39 . The system of  claim 38  wherein the controller is adapted for interacting with (1) the fabricating device and (2) the DBD treatment device.  
     
     
         40 . The system of  claim 38  wherein the interlock feature is adapted for interacting with the DBD treatment device.  
     
     
         41 . The system of  claim 40  wherein the interlock feature is adapted for stopping the plasma treatment upon an occurrence of a pre-defined processing condition.  
     
     
         42 . A semiconductor processing system comprising: 
 a) a semiconductor fabricating device;    b) a pump integrated DBD treatment apparatus comprising: (1) n vacuum pump stages and (2) n minus 2 DBD treatment devices integrated with the n vacuum pump stages wherein each of the n minus 2 DBD treatment devices comprises at least one DBD cell including: (i) a substantially cylindrical dielectric tube having an outside surface, (ii) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (iii) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein the second electrode is positioned a distance D from the first electrode and the first and second electrodes are placed in a side-by-side position and (iv) an AC power supply electrically connected to the first and second electrodes, such that the power supply is adapted for energizing the cell to form a plasma when a gas is present inside the tube; and    c) a gas flow connection between the fabricating device and the pump integrated DBD treatment apparatus.    
     
     
         43 . The system of  claim 42  wherein the n vacuum pump stages each comprise a Roots vacuum pump stage.  
     
     
         44 . The system of  claim 42  wherein the AC power supply comprises a switched mode resonant high voltage power supply.  
     
     
         45 . A chemical processing system comprising: 
 a) a chemical processing device;    b) a DBD cell including: (1) a substantially cylindrical dielectric tube having an outside surface, (2) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube;    and (3) a second electrically conductive electrode positioned on the outside of the tube and encircling the tube, wherein (i) the second electrode is positioned a distance D from the first electrode and (ii) the first and second electrodes are placed in a side-by-side position; and    c) a gas flow connection between the processing device and the tube.    
     
     
         46 . A method of treating a first gas, the method comprising: 
 a) energizing a first DBD cell including: a substantially cylindrical dielectric tube having (1) an inside, (2) an outside surface, (3) a first electrically conductive electrode positioned on the outside surface of the tube and encircling the tube, and (4) a second electrically conductive electrode positioned on the outside surface of the tube and encircling the tube, wherein (i) the second electrode is positioned a distance D from the first electrode and (ii) the first and second electrodes are placed in a side-by-side position;    b) flowing the first gas through the inside of the tube; and    c) generating a first plasma in the gas through dielectric barrier discharge inside the tube, wherein a first treated gas is formed.    
     
     
         47 . The method of  claim 46  wherein distance D ranges from about 10 mm to about 30 mm.  
     
     
         48 . The method of  claim 46  wherein the first and second electrodes comprise shapes selected from the group consisting of rings and cylindrical bands.  
     
     
         49 . The method of  claim 46  wherein the first and second electrodes include heat exchange elements.  
     
     
         50 . The method of  claim 46  wherein the first gas comprises one or more gases selected from the group of gases consisting of fluorocarbon gas, NF 3 , mixtures of fluorocarbon gas and inert gas, and mixtures of NF 3  and inert gas.  
     
     
         51 . The method of  claim 46  wherein the first gas comprises one or more gases that are discharged from a semiconductor fabricating device.  
     
     
         52 . The method of  claim 46  wherein the first gas comprises one or more gases that are discharged from a chemical processing device.  
     
     
         53 . The method of  claim 46  additionally comprising adding a second gas to the first gas, such that the first and second gas form a gaseous mixture.  
     
     
         54 . The method of  claim 53  wherein the second gas comprises a gas that is capable of reacting with the first gas, when the first plasma is generated in the tube.  
     
     
         55 . The method of  claim 53  wherein the second gas is added before the first gas flows through the first cell.  
     
     
         56 . The method of  claim 55  wherein the gaseous mixture is pre-treated prior to flowing the gaseous mixture through the first cell.  
     
     
         57 . The method of  claim 53  additionally comprising analyzing the composition of the first treated gas.  
     
     
         58 . The method of  claim 53  wherein the second gas is added to the first gas between the first electrode and the second electrode.  
     
     
         59 . The method of  claim 46  additionally comprising analyzing the gas composition of the first treated gas.  
     
     
         60 . The method of  claim 46  wherein energizing the first cell comprises activating a first AC power supply.  
     
     
         61 . The method of  claim 60  wherein activating the first power supply comprises controlling the first power supply employing one or more techniques selected from the group consisting of analyzing the first treated gas, determining gas pressure inside the tube and determining tube temperature.  
     
     
         62 . The method of  claim 59  wherein the first power supply comprises a switched mode resonant high voltage power supply.  
     
     
         63 . The method of  claim 59  wherein the first power supply comprises: 
 a) a DC power supply;  
 b) a capacitor in parallel with the DC power supply; and  
 c) electrical components connected in series including: (1) an inductor, (2) a primary winding of a transformer and (3) a MOSFET switch having a snubber capacitor in parallel with the switch and wherein the series is in parallel with the DC power supply.  
 
     
     
         64 . The method of  claim 46  additionally comprising: 
 a) energizing a second DBD cell including (1) the tube, (2) a third electrically conductive electrode positioned on the outside surface of the tube and encircling the tube and (3) a fourth electrically conductive electrode positioned on the outside of the tube, wherein the third and fourth electrodes are in a side-by-side position;  
 b) flowing the first treated gas through the inside of the tube positioned at the second DBD cell;  
 c) generating a second plasma in the first treated gas through dielectric barrier discharge inside the second cell, wherein a second treated gas is formed.  
 
     
     
         65 . The method of  claim 64  wherein energizing the second cell comprises activating a second AC power supply.  
     
     
         66 . The method of  claim 65  wherein the first and second AC power supplies are controlled independently.  
     
     
         67 . The method of  claim 64  wherein the first and second DBD cells are energized independently of each other.  
     
     
         68 . The method of  claim 64  additionally comprising analyzing a composition of the first treated gas prior to introducing the first treated gas into the second DBD cell, thereby obtaining first analytical results.  
     
     
         69 . The method of  claim 68  wherein generating the second plasma comprises controlling the second plasma employing the analytical results.  
     
     
         70 . The method of  claim 69 , additionally comprising introducing a third gas between the first and second cells.  
     
     
         71 . The method of  claim 46  additionally comprising: 
 a) flowing the first gas through a first vacuum pumping stage before flowing the gas through the tube; and  
 b) flowing the first treated gas through a second vacuum pumping stage, wherein the first and second pumping stages are integrated with the first cell.