Patent Publication Number: US-2010119984-A1

Title: Abatement system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/113,143, filed Nov. 10, 2008, the entire contents of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     1) Field 
     Embodiments of the present invention pertain to the field of abatement systems and, in particular, to a fuel burner ring for a combustion chamber in an abatement system and to a fuel flow control for an abatement system. 
     2) Description of Related Art 
     Abatement systems can provide environmental abatement solutions for the semiconductor, solar and display industries. A wide range of point-of-use scrubbing systems are available, including wet, dry, thermal and integrated technologies for abatement of toxic and hazardous exhaust gases for a variety of applications. For example, some abatement systems handle complex effluent challenges ranging from a single unit to an entire fabrication facility. 
     SUMMARY 
     Embodiments of the present invention include abatement systems. 
     In an embodiment, an abatement system includes a combustion chamber. The abatement system also includes a fuel burner ring. The fuel burner ring is coupled with the combustion chamber. 
     In another embodiment, an abatement system includes a combustion chamber. The abatement system also includes a fuel flow control mechanism. The fuel flow control mechanism is coupled with the combustion chamber. 
     In yet another embodiment, an abatement system includes a combustion chamber. The abatement system also includes a fuel burner ring and a fuel flow control mechanism. Both the a fuel burner ring and the fuel flow control mechanism are coupled with the combustion chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a block-diagram of an abatement system, in accordance with an embodiment of the present invention. 
         FIG. 2  illustrates a cross-sectional view of an abatement system, in accordance with an embodiment of the present invention. 
         FIG. 3  illustrates a cross-sectional view of a conventional arrangement of four process gas inlet tubes, each surrounded by four nozzles for injection combustion fuel. 
         FIG. 4  illustrates a cross-sectional view of an arrangement of four process gas inlet tubes, each surrounded by a burner ring for injecting combustion fuel, in accordance with an embodiment of the present invention. 
         FIG. 5  is a temperature distribution map representing temperature distribution for a ring burner used approximately in a temperature range of 300-900 Kelvin, in accordance with an embodiment of the present invention. 
         FIG. 6  is a temperature distribution map representing temperature distribution for four conventional nozzles used approximately in a temperature range of 300-2200 Kelvin. 
         FIG. 7  illustrates various views of a portion of an abatement system including a combustion chamber having a fuel burner ring, in accordance with an embodiment of the present invention. 
         FIG. 8  illustrates various views of a burner ring for use in an abatement system including a combustion chamber, in accordance with an embodiment of the present invention. 
         FIG. 9  illustrates a diagram of a vacuum generator device, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Abatement systems are described. In the following description, numerous specific details are set forth, such as system configuration, in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well-known features, such as facility layouts, are not described in detail in order to not unnecessarily obscure embodiments of the present invention. Furthermore, it is to be understood that the various embodiments shown in the Figures are illustrative representations and are not necessarily drawn to scale. 
     Disclosed herein are abatement systems. In one embodiment, an abatement system includes a combustion chamber and a fuel burner ring coupled with the combustion chamber. In one embodiment, an abatement system includes a combustion chamber and a fuel flow control mechanism coupled with the combustion chamber. In one embodiment, an abatement system includes a combustion chamber, a fuel burner ring, and a fuel flow control mechanism, both the fuel burner ring and the fuel flow control mechanism coupled with the combustion chamber. 
     In accordance with an embodiment of the present invention, an abatement system destroys residual process gases through active flame oxidation and combustion for reliable and safe abatement. In one embodiment, effluent gases are heated by a flame in the main chamber of the system which provides ignition of flammable and pyrophoric gas by-products. In a specific embodiment, the advanced design of the flame ignition system ensures a stable flame with high inert gas flow. In an embodiment, an abatement system provides wet-scrubbing solutions that support up to four process effluent streams including those from challenging processes such as epitaxial silicon deposition and metal etch. In one embodiment, the abatement system handles perfluorocarbons (PFCs) and global-warming gasses. In another embodiment, the treatment of hydride and acid-based gases is performed in an abatement system. In one embodiment, by utilizing chemisorptive technology, process gases and by-products react with resin to form nonvolatile solids, an irreversible process that traps by-products and ensures safe disposal of the resin. 
     In an aspect of the present invention, an abatement system may include a combustion chamber or reactor.  FIG. 1  illustrates a block-diagram of an abatement system, in accordance with an embodiment of the present invention. Referring to  FIG. 1 , abatement system  100  includes a gas inlet  102 , a combustion chamber or reactor  104 , a cooling chamber  106 , a receiving tank  108 , a scrubber  110 , and an exhaust  112 . In one embodiment, combustion chamber or reactor  104  includes a burner. In another embodiment, cooling chamber  106  is a waterfall cooling chamber configured with spray jets to spray water into a gas stream. In an embodiment, receiving tank  108  includes a large tank holding an amount of water at the bottom of the tank with space over-head for gas that is moving through the abatement system. In another embodiment, scrubber  110  sits directly above receiving tank  108 . In a specific embodiment, scrubber  110  includes a spray shower for spraying water into a stream of effluent gases. 
       FIG. 2  illustrates a cross-sectional view of an abatement system, in accordance with an embodiment of the present invention. Referring to  FIG. 2 , abatement system  200  includes a gas inlet  202 , a combustion chamber or reactor  204 , a cooling chamber  206 , a receiving tank  208 , a scrubber  210 , and an exhaust  212 . In one embodiment, combustion chamber or reactor  204  includes a burner. In another embodiment, cooling chamber  206  is a waterfall cooling chamber configured with spray jets to spray water into a gas stream. In an embodiment, receiving tank  208  includes a large tank holding an amount of water at the bottom of the tank with space over-head for gas that is moving through the abatement system, as is depicted in  FIG. 2 . In another embodiment, scrubber  210  sits directly above receiving tank  208 , as is also depicted in  FIG. 2 . In a specific embodiment, scrubber  210  includes a spray shower for spraying water into a stream of effluent gases. 
     An abatement system may include a combustion chamber having a fuel burner ring. In accordance with an embodiment of the present invention, an abatement system uses combustion to heat a process gas to a sufficiently to a sufficiently high temperature and for a sufficient duration for abatement. However, an abatement system using burners composed of one or a few large jets may provide non-uniform temperature and flow distributions, which can degrade the performance of the abatement system. The degraded performance may result from some of the process gas not reaching a required temperature and, thus, high velocity gas may exit a reaction chamber before a combustion reaction is complete. Instead, in one embodiment, a burner ring with many small ports is used and is coupled to the combustion chamber of an abatement system. In a specific embodiment, by using a burner ring with many small ports, a more uniform flow pattern is generated along the length of the reaction chamber. 
     In an exemplary embodiment of the present invention, the reaction chamber of an Erika™ abatement system, available from Applied Materials, Inc., is equipped with a fuel burner ring instead of a conventional arrangement process using four nozzles. In another exemplary embodiment of the present invention, the reaction chamber of an Integrated Subfab System (ISS) abatement system or a Marathon™ abatement system, available from Applied Materials, Inc., is equipped with a fuel burner ring instead of a conventional arrangement process using four nozzles. In an embodiment, gases are introduced to a reaction chamber of the abatement system through four inlet tubes. In a conventional arrangement, each inlet tube is surrounded by up to four nozzles. For example,  FIG. 3  illustrates a cross-sectional view of a conventional arrangement of four process gas inlet tubes  300 , each surrounded by four nozzles  302  for injecting combustion fuel. By contrast,  FIG. 4  illustrates a cross-sectional view of an arrangement of four process gas inlet tubes  400 , each surrounded by a burner ring  402  having holes  404  for injecting combustion fuel, in accordance with an embodiment of the present invention. In an embodiment, the holes  404  in each burner ring  402  are coupled to a single plenum to obtain uniform flow around the ring. In one embodiment, by distributing the fuel flow over a large number of holes, the velocity at each burner ring is reduced to be approximately the same as the velocity of a process gas in each process gas inlet tube  400 . In a specific embodiment, a range of approximately 8-30 holes  404  are included in each burner ring  402 . In an embodiment, by reducing the fuel velocity surrounding each process gas inlet tube  400 , heating in a combustion chamber of an abatement system is more uniform, improving the overall performance of the abatement system. 
     By using a fuel burner ring, the temperature distribution in a reaction chamber may be more uniform. For example,  FIG. 5  is a temperature distribution map  500  representing temperature distribution for a ring burner used approximately in a temperature range of 300-900 Kelvin, in accordance with an embodiment of the present invention. By contrast,  FIG. 6  is a temperature distribution map  600  representing temperature distribution for four conventional nozzles used approximately in a temperature range of 300-2200 Kelvin. 
       FIG. 7  illustrates various views of a portion of an abatement system including a combustion chamber having a fuel burner ring, in accordance with an embodiment of the present invention. Referring to  FIG. 7 , in one embodiment, a bottom view  790  of a cover  710  of a reaction chamber for an abatement system includes four process gas inlet tubes  700 , each surrounded by a burner ring  702  having holes  704  for injecting combustion fuel. Referring to  FIG. 7 , in another embodiment, a top view  799  of a cover  710  of a reaction chamber for an abatement system includes four process gas inlet tubes  700 .  FIG. 8  illustrates various views of a burner ring for use in an abatement system including a combustion chamber, in accordance with an embodiment of the present invention. Referring to  FIG. 8 , a burner ring  802  includes holes  804  for injecting combustion fuel into a reaction chamber in an abatement system. 
     Thus, an abatement system with a fuel burner ring may be provided. In an embodiment, an abatement system includes a combustion chamber and a fuel burner ring coupled with the combustion chamber. In one embodiment, the fuel burner ring includes a plurality of ports. In a specific embodiment, the plurality of ports is arranged to provide an approximately uniform flow pattern of a fuel provided to the plurality of ports. In a particular embodiment, the approximately uniform flow pattern of the fuel is provided along a length of the combustion chamber. In another particular embodiment, the abatement system further includes a process gas inlet tube to introduce a process gas into the combustion chamber, the process gas inlet tube surrounded by the fuel burner ring. In another particular embodiment, the abatement further includes one or more additional process gas inlet tubes, each of the one or more additional process gas inlet tubes surrounded by a fuel burner ring. In an embodiment, the fuel burner ring includes a number of ports approximately in the range of 8-30 ports. 
     In another aspect of the present invention, an abatement system may include a fuel flow control mechanism. In accordance with an embodiment of the present invention, the ratio of fuel to air in a pilot or main burner in a combustion abatement device are controlled to prevent flashback, loss of flame, and sooting. Conventional systems may require several devices or software control to maintain the proper ratio while still allowing for variable set-points. Other designs do not even allow for adequate mixing of the air and the fuel. Accordingly, in some facilities, e.g. facilities with low fuel pressure, the fuel pressure supplied by the facility may be too low for some flow control devices. 
     Instead, in accordance with an embodiment of the present invention, an abatement system is equipped with a vacuum generator device that is driven by high pressure air. In one embodiment, the high pressure air creates a slight vacuum to draw gaseous fuel into the device, even when supply pressure is too low. In a specific embodiment, the fuel is a gas such as, but not limited to, methane or a natural gas composition. In an embodiment, for a given fuel pressure, the fuel to air ratio is determined by the design of the vacuum generator device. In one embodiment, the vacuum generator device can be used alone with no other control required. In a specific embodiment, this eliminates the need for separate flow controllers and software input on the air and fuel lines. In another embodiment, the fuel pressure is fixed by a pressure regulator. In accordance with an embodiment of the present invention, air flow is adjusted in the vacuum generator device for various operating condition selection. In one embodiment, the adjustment is performed by a flow or pressure control device coupled to the vacuum generator device. In another embodiment, the vacuum generator device also acts as a mixer for the fuel and air, improving the stability of a flame within a reaction chamber of an abatement system. In an exemplary embodiment,  FIG. 9  illustrates a diagram of a vacuum generator device  900 , in accordance with an embodiment of the present invention. In a specific embodiment, vacuum generator device  900  is a venturi device, as illustrated in  FIG. 9 . 
     Thus, an abatement system with a fuel flow control mechanism may be provided. In an embodiment, an abatement system includes a combustion chamber and a fuel flow control mechanism coupled with the combustion chamber. In one embodiment, the fuel flow control mechanism includes a vacuum generator device configured to be driven by a high pressure airflow. In a specific embodiment, the vacuum generator device is configured such that the high pressure airflow creates a slight vacuum for drawing gaseous fuel into the vacuum generator device. In a particular embodiment, the vacuum generator device is the sole fuel flow control mechanism in the abatement system. In another particular embodiment, the vacuum generator device is further coupled with a pressure regulator as an additional fuel flow control mechanism in the abatement system. In another particular embodiment, the vacuum generator device is further configured to mix a fuel flow and an airflow. 
     In another aspect of the present invention, an abatement system may include a fuel burner ring and a fuel flow control mechanism. In an embodiment, an abatement system includes a combustion chamber, a fuel burner ring coupled with the combustion chamber, and a fuel flow control mechanism also coupled with the combustion chamber. In one embodiment, the fuel burner ring includes a plurality of ports, and the fuel flow control mechanism includes a vacuum generator device configured to be driven by a high pressure airflow. In a specific embodiment, the vacuum generator device is configured such that the high pressure airflow creates a slight vacuum for drawing a fuel into the vacuum generator device, and the plurality of ports is arranged to provide an approximately uniform flow pattern of the fuel provided to the plurality of ports. In a particular embodiment, the approximately uniform flow pattern of the fuel is provided along a length of the combustion chamber, and the vacuum generator device is the sole fuel flow control mechanism in the abatement system. In another particular embodiment, the vacuum generator device is further coupled with a pressure regulator as an additional fuel flow control mechanism in the abatement system, and the abatement system further includes a process gas inlet tube to introduce a process gas into the combustion chamber, the process gas inlet tube surrounded by the fuel burner ring. In another particular embodiment, the vacuum generator device is further configured to mix a fuel flow and an airflow, and the abatement system further includes one or more additional process gas inlet tubes, each of the one or more additional process gas inlet tubes surrounded by a fuel burner ring. In an embodiment, the fuel burner ring includes a number of ports approximately in the range of 8-30 ports. 
     Thus, abatement systems have been disclosed. In accordance with an embodiment of the present invention, an abatement system includes a combustion chamber and a fuel burner ring coupled with the combustion chamber. In one embodiment, the fuel burner ring includes a plurality of ports. In accordance with another embodiment of the present invention, an abatement system includes a combustion chamber and a fuel flow control mechanism coupled with the combustion chamber. In one embodiment, the fuel flow control mechanism includes a vacuum generator device configured to be driven by a high pressure airflow.