Abstract:
Embodiments disclosed herein include an abatement system for abating compounds produced in semiconductor processes. The abatement system includes an exhaust cooling apparatus located downstream of a plasma source. The exhaust cooling apparatus includes at least one cooling plate a device for introducing turbulence to the exhaust flowing within the exhaust cooling apparatus. The device may be a plurality of fins, a cylinder with a curved top portion, or a diffuser with angled blades. The turbulent flow of the exhaust within the exhaust cooling apparatus causes particles to drop out of the exhaust, minimizing particles forming in equipment downstream of the exhaust cooling apparatus.

Description:
BACKGROUND 
     Field 
       [0001]    Embodiments of the present disclosure generally relate to semiconductor processing equipment. More particularly, embodiments of the present disclosure relate to an abatement system and a vacuum processing system for abating compounds produced in semiconductor processes. 
       Description of the Related Art 
       [0002]    The process gases used by semiconductor processing facilities include many compounds, such as perfluorocarbons (PFCs), which must be abated or treated before disposal, due to regulatory requirements and environmental and safety concerns. Typically, a remote plasma source may be coupled to a processing chamber to abate the compounds coming out of the processing chamber. A reagent may be injected into the plasma source to assist the abatement of the compounds. 
         [0003]    Conventional abatement technology for abating PFCs utilizes water vapor as a reagent, which provides good destruction removal efficiency (DRE). However, abatement of certain compounds using water vapor in the remote plasma source can result in the formation of solid particles in the remote plasma source and equipment downstream of the remote plasma source, such as exhaust line and pumps. In addition, the exhaust exiting the remote plasma source may be at an elevated temperature, which can cause issues at the pump downstream of the remote plasma source. 
         [0004]    Accordingly, what is needed in the art is an improved abatement system for abating compounds produced in semiconductor processes. 
       SUMMARY 
       [0005]    Embodiments of the present disclosure relate to an abatement system and a vacuum processing system for abating compounds produced in processes. In one embodiment, an exhaust cooling apparatus includes a body having an inlet and an outlet and a plurality of cooling plates disposed within the body. The plurality of cooling plates form a serpentine passage. 
         [0006]    In another embodiment, an exhaust cooling apparatus includes a body having an inlet and an outlet and a plurality of hollow cylinders disposed within the body. The plurality of hollow cylinders are concentric. 
         [0007]    In another embodiment, an exhaust cooling apparatus includes a body having an inlet and an outlet, a cooling plate disposed within the body, and a device disposed over the cooling plate. The device includes a wall and a plate coupled to the wall. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
           [0009]      FIG. 1  is a schematic side view of a vacuum processing system including an exhaust cooling apparatus according to one embodiment described herein. 
           [0010]      FIG. 2A  is a schematic cross-sectional view of the exhaust cooling apparatus according to one embodiment described herein. 
           [0011]      FIG. 2B  is a schematic cross-sectional view of the exhaust cooling apparatus according to another embodiment described herein. 
           [0012]      FIG. 2C  is a schematic cross-sectional top view of cylinders and coupling members according to one embodiment described herein. 
           [0013]      FIG. 3  is a cross-sectional view of the exhaust cooling apparatus according to one embodiment described herein. 
           [0014]      FIG. 4  is a cross-sectional view of the exhaust cooling apparatus according to one embodiment described herein. 
           [0015]      FIG. 5  is a cross-sectional view of the exhaust cooling apparatus according to one embodiment described herein. 
           [0016]      FIG. 6  is a cross-sectional view of the exhaust cooling apparatus according to one embodiment described herein. 
           [0017]      FIG. 7A  is a perspective view of a portion of a liner according to one embodiment described herein. 
           [0018]      FIG. 7B  is a perspective view of a liner according to one embodiment described herein. 
           [0019]      FIG. 8  is a cross-sectional view of the exhaust cooling apparatus according to one embodiment described herein. 
           [0020]      FIG. 9  is a cross-sectional view of the exhaust cooling apparatus according to one embodiment described herein. 
       
    
    
       [0021]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
       DETAILED DESCRIPTION 
       [0022]      FIG. 1  is a schematic side view of a vacuum processing system  170  having an exhaust cooling apparatus  117  utilized in an abatement system  193 . The vacuum processing system  170  includes at least a vacuum processing chamber  190 , a plasma source  100 , and the exhaust cooling apparatus  117 . The abatement system  193  includes at least the plasma source  100  and the exhaust cooling apparatus. The vacuum processing chamber  190  is generally configured to perform at least one integrated circuit manufacturing process, such as a deposition process, an etch process, a plasma treatment process, a preclean process, an ion implant process, or other integrated circuit manufacturing process. The process performed in the vacuum processing chamber  190  may be plasma assisted. For example, the process performed in the vacuum processing chamber  190  may be a plasma deposition process for depositing a silicon-based material or a plasma etch process for removing a silicon-based material. 
         [0023]    The vacuum processing chamber  190  has a chamber exhaust port  191  coupled to the plasma source  100  of the abatement system  193  via a foreline  192 . The exhaust cooling apparatus  117  is coupled to an exhaust of the plasma source  100  in order to cool the exhaust coming out of the plasma source and to collect particles formed in the plasma source. The exhaust cooling apparatus  117  is coupled to an exhaust conduit  194  to pumps and facility exhaust, schematically indicated by a single reference numeral  196  in  FIG. 1 . The pumps are generally utilized to evacuate the vacuum processing chamber  190 , while the facility exhaust generally includes scrubbers or other exhaust cleaning apparatus for preparing the effluent of the vacuum processing chamber  190  to enter the atmosphere. 
         [0024]    The plasma source  100  is utilized to perform an abatement process on gases and/or other materials exiting the vacuum processing chamber  190  so that such gases and/or other materials may be converted into a more environmentally and/or process equipment friendly composition. In some embodiments, an abatement reagent source  114  is couple to the foreline  192  and/or the plasma source  100 . The abatement reagent source  114  provides an abatement reagent into the plasma source  100  which may be energized to react with or otherwise assist converting the materials to be exiting the vacuum processing chamber  190  into a more environmentally and/or process equipment friendly composition. Optionally, a purge gas source  115  may be coupled to the plasma source  100  for reducing deposition on components inside the plasma source  100 . 
         [0025]    The exhaust cooling apparatus  117  is coupled between the plasma source  100  and the exhaust conduit  194  for reducing the temperature of the exhaust coming out of the plasma source  100  and for collecting particles formed in the plasma source  100 . In one example, the exhaust cooling apparatus  117  is a part of the abatement system  193 . 
         [0026]    Optionally, a pressure regulating module  182  may be coupled to at least one of the plasma source  100  or the exhaust conduit  194 . The pressure regulating module  182  injects a pressure regulating gas, such as Ar, N, or other suitable gas which allows the pressure within the plasma source  100  to be better controlled, and thereby provide more efficient abatement performance. In one example, the pressure regulating module  182  is a part of the abatement system  193 . 
         [0027]      FIG. 2A  is a schematic cross-sectional view of the exhaust cooling apparatus  117  according to one embodiment described herein. As shown in  FIG. 2A , the exhaust cooling apparatus  117  includes a body  202  having an inlet  204 , an outlet  206 , a first wall  208 , and a second wall  210  opposite the first wall  208 . A plurality of cooling plates  212 ,  214 ,  216  may be coupled to the first wall  208  and/or second wall  210  along a width  217  of the exhaust cooling apparatus  117 . The width  217  of the exhaust cooling apparatus  117  is defined between the inlet  204  and the outlet  206 . The exhaust cooling apparatus  117  may have a length  219  defined between the first wall  208  and the second wall  210 . Each cooling plate  212 ,  214 ,  216  may have a length  221  that is less than the length  219  of the exhaust cooling apparatus  117 . The length  221  of each cooling plate  212 ,  214 ,  216  may be the same or may be different. Each cooling plate  212 ,  214 ,  216  may have a width (into the paper) that is the same as the thickness (into the paper) of the exhaust cooling apparatus  117 . 
         [0028]    The exhaust exiting the plasma source  100  enters the exhaust cooling apparatus  117  via the inlet  204  and exits the exhaust cooling apparatus  117  via the outlet  206 . The exhaust may flow along a serpentine passage  218  formed by the plurality of cooling plates  212 ,  214 ,  216 . The plurality of cooling plates  212 ,  214 ,  216  may be alternately coupled to opposite walls  208 ,  210  and gaps  220 ,  222 ,  224  may be formed between cooling plates  212 ,  214 ,  216  and a wall opposite the wall the cooling plates  212 ,  214 ,  216  are coupled thereto, respectively. For example, as shown in  FIG. 2A , the cooling plate  212  is coupled to the second wall  210 , and the gap  220  is formed between the cooling plate  212  and the first wall  208 . An adjacent cooling plate (i.e., cooling plate  214 ) to the cooling plate  212  is coupled to the first wall  208 , and the gap  222  is formed between the cooling plate  214  and the second wall  210 . An adjacent cooling plate (i.e., cooling plate  216 ) to the cooling plate  214  is coupled to the second wall  210 , and the gap  224  is formed between the cooling plate  216  and the first wall  208 . The gaps  220 ,  222 ,  224  may be large enough to ensure no pressure buildup inside the exhaust cooling apparatus  117 . In some embodiments, since the width of each cooling plate  212 ,  214 ,  216  is the same as the thickness of the exhaust cooling apparatus  117 , exhaust flowing through the exhaust cooling apparatus  117  passes the plurality of cooling plates  212 ,  214 ,  216  via gaps  220 ,  222 ,  224 , respectively. In other embodiments, the width of each cooling plate  212 ,  214 ,  216  may be smaller than the thickness of the exhaust cooling apparatus  117 , exhaust flowing through the exhaust cooling apparatus  117  passes the plurality of cooling plates  212 ,  214 ,  216  not only via gaps  220 ,  222 ,  224 , respectively, but also via gaps formed between cooling plates  212 ,  214 ,  216  and walls defining the thickness of the exhaust cooling apparatus  117 . 
         [0029]    The cooling plates  212 ,  214 ,  216  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. A channel (not shown) may be formed in each cooling plate  212 ,  214 ,  216  for flowing a coolant therethrough. Having the coolant flowing through each cooling plate  212 ,  214 ,  216  causes the temperature of each cooling plate  212 ,  214 ,  216  to be less than the temperature of the exhaust entering the exhaust cooling apparatus  117 . The exhaust entering the exhaust cooling apparatus  117  is cooled by the cooling plates  212 ,  214 ,  216 , and cooled surfaces of the cooling plates  212 ,  214 ,  216  also condense solid particles in the exhaust, preventing solid by-product materials from exiting the exhaust cooling apparatus  117  and reaching pumps and facility exhaust  196 . In one embodiment, the cooling plates  212 ,  214 ,  216  do not include the channel for a coolant to flow therethrough, and the temperature of the surfaces of the cooling plates  212 ,  214 ,  216  is low enough to cool the exhaust and to condense solid particles in the exhaust. The number of cooling plates  212 ,  214 ,  216  located within the exhaust cooling apparatus may range from two to  10 . 
         [0030]      FIG. 2B  is a schematic cross-sectional view of the exhaust cooling apparatus  117  according to another embodiment described herein. As shown in  FIG. 2B , the exhaust cooling apparatus  117  includes a body  230  having an inlet  232 , an outlet  234 , a first wall  236 , and a second wall  238  opposite the first wall  236 . A plurality of cylinders  240 ,  242 ,  244  may be located within the body  230  of the exhaust cooling apparatus  117 . The cylinders  240 ,  242 ,  244  may be hollow and concentric, such that the cylinder  244  is disposed within the cylinder  242 , and the cylinder  242  is disposed within the cylinder  240 . The body  230  of the exhaust cooling apparatus  117  may be a hyper-rectangle, as shown in  FIG. 2B , or the body  230  may be a hollow cylinder that is concentric with the plurality of cylinders  240 ,  242 ,  244 . 
         [0031]    Each of the plurality of cylinders  240 ,  242 ,  244  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. Coupling members  246  may be utilized to couple the cylinder  240  to the walls  236 ,  238 , and coupling members  248  may be utilized to couple the cylinders  240 ,  242 ,  244  to each other. Additional coupling members  250  may be utilized to couple the cylinder  240  to the walls  236 ,  238 , and coupling members  252  may be utilized to couple the cylinders  240 ,  242 ,  244  to each other.  FIG. 2C  is a cross-sectional top view of the cylinders  240 ,  242 ,  244  and coupling members  246 ,  248 . Coupling members  246 ,  248 ,  250 ,  252  may be made of the same material as the cylinders  240 ,  242 ,  244 . In some embodiments, a channel (not shown) may be formed in the coupling members  246 ,  248 ,  250 ,  252  and the cylinders  240 ,  242 ,  244  for flowing a coolant therethrough. 
         [0032]    Referring back to  FIG. 2B , having the coolant flowing through each cylinder  240 ,  242 ,  244  causes the temperature of each cylinder  240 ,  242 ,  244  to be less than the temperature of the exhaust entering the exhaust cooling apparatus  117 . The exhaust entering the exhaust cooling apparatus  117  flows through gaps formed between the cylinders  240 ,  242 ,  244  and between the cylinder  240  and the walls  236 ,  238 . The exhaust is cooled by the cylinders  240 ,  242 ,  244 , and cooled surfaces of the cylinders  240 ,  242 ,  244  also condense solid particles in the exhaust, preventing solid by-product materials from exiting the exhaust cooling apparatus  117  and reaching pumps and facility exhaust  196 . In one embodiment, the cylinders  240 ,  242 ,  244  do not include the channel for a coolant to flow therethrough, and the temperature of the surfaces of the cylinders  240 ,  242 ,  244  is low enough to cool the exhaust and to condense solid particles in the exhaust. The number of cylinders  240 ,  242 ,  244  located within the exhaust cooling apparatus may range from two to five. 
         [0033]      FIG. 3  is a cross-sectional view of the exhaust cooling apparatus  117  according to one embodiment described herein. As shown in  FIG. 3 , the exhaust cooling apparatus  117  includes a body  302  having an inlet  304 , an outlet  306 , a first end  307 , a second end  309  opposite the first end  307 , and a wall  308  between the inlet  304  and the outlet  306  and between the first end  307  and the second end  309 . The second end  309  may be removably coupled to the wall  308 . The wall  308  may be cylindrical, as shown in  FIG. 3 . The exhaust cooling apparatus  117  may include a first liner  310  adjacent to the inlet  304 , a second liner  312  adjacent to the outlet  306 , and a cooling plate  314  disposed between the first liner  310  and the second liner  312 . The first liner  310 , the second liner  312 , and the cooling plate  314  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. The cooling plate  314  may be coupled to the first end  307 . The first liner  310  may be coupled to the second end  309  and the second liner  312  may be coupled to the second end  309 . The cooling plate  314  may include a plurality of through holes  316 . The diameters of each through hole  316  may be sufficiently large so there is minimum to no pressure build-up. In one embodiment, the through holes  316  each have a diameter of about 0.5 inches and the pressure restriction is less than about 100 mTorr. A channel (not shown) may be formed in the cooling plate  314  for flowing a coolant therethrough. Having the coolant flowing through the cooling plate  314  causes the temperature of the cooling plate  314  to be less than the temperature of the exhaust entering the exhaust cooling apparatus  117 . The exhaust entering the exhaust cooling apparatus  117  is cooled by the cooling plate  314  as the exhaust passes through the through holes  316 . In one embodiment, the cooling plate  314  does not include the channel for a coolant to flow therethrough, and the temperature of the surfaces of the cooling plate  314  is low enough to cool the exhaust. 
         [0034]    In order to trap particles in the exhaust cooling apparatus  117 , a device is utilized to introduce turbulence to the exhaust flowing within the exhaust cooling apparatus  117  adjacent a cooled structure with high conductance to prevent a pressure increase in exhaust cooling apparatus  117 . The cooled structure with high conductance may be the cooling plate  314 , and the device may be a plate  318  and a plurality of fins  320 ,  322 ,  324 ,  326 ,  328  extending from the plate  318 . The plurality of fins  320 ,  322 ,  324 ,  326 ,  328  may be coupled to the plate  318  or may be formed integrally with the plate  318 . The plate  318  and the plurality of fins  320 ,  322 ,  324 ,  326 ,  328  may be part of the first liner  310 . The plate  318  may be substantially parallel to the cooling plate  314 . The plate  318  may also include one or more openings  330  for allowing the exhaust to pass through. The plurality of fins  320 ,  322 ,  324 ,  326 ,  328  extending from the plate  318  are utilized to create turbulence in the exhaust as the exhaust enters the exhaust cooling apparatus via the inlet  304 . The number of fins may be any suitable number sufficient to cause turbulence in the exhaust within the exhaust cooling apparatus. In one embodiment, five fins are utilized, as shown in  FIG. 3 . 
         [0035]    Each fin  320 ,  322 ,  324 ,  326 ,  328  may form an acute or right angle with respect to the plate  318 . In one embodiment, the fin  324  is a center fin such that fins located on either sides of the fin  324  are mirror images of each other. For example, the fin  324  may form an angle A 1  with respect to the plate  318 , the fins  320 ,  328  are mirror images of each other and may form an angle A 2  with respect to the plate  318 , and the fins  322 ,  326  are mirror images of each other and may form an angle A 3  with respect to the plate  318 . In one embodiment, the angle A 1  is about 90 degrees and the angle A 2  is greater than the angle A 3 . The angle the fins form with respect to the plate  318  may be any suitable angle in order to cause turbulence in the exhaust in the exhaust cooling apparatus. 
         [0036]    During operation, exhaust exiting the plasma source  100  ( FIG. 1 ) enters the exhaust cooling apparatus  117  via the inlet  304 . The flow of the exhaust becomes turbulent as the exhaust flows passing the fins  320 ,  322 ,  324 ,  326 ,  328  and the plate  318 , causing particles to drop out of the exhaust. Some particles may be collected on the plate  318 , and some particles may be collected on the second liner  312 , as the exhaust passes through the openings  330  in the plate  318  and through holes  316  in the cooling plate  314 . The second end  309 , along with the first liner  310  and the second liner  312 , may be pulled out of the exhaust cooling apparatus in order to remove the particles collected on the plate  318  and on the second liner  312 . The pressure inside the exhaust cooling apparatus  117  during operation is monitored by a pressure sensor  313 . The pressure sensor  313  may be coupled to the second end  309 , as shown in  FIG. 3 . 
         [0037]      FIG. 4  is a cross-sectional view of the exhaust cooling apparatus  117  according to one embodiment described herein. As shown in  FIG. 4 , the exhaust cooling apparatus  117  includes a body  402  having an inlet  404 , an outlet  406 , a wall  408  between the inlet  404  and the outlet  406 , and a collection device  410  coupled to the wall  408 . The wall  408  may be cylindrical, as shown in  FIG. 4 . The exhaust cooling apparatus  117  may include an end  414  between the inlet  404  and the outlet  406  and a cooling plate  412  coupled to the end  414 . The cooling plate  412  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. A channel (not shown) may be formed in the cooling plate  412  for flowing a coolant therethrough. Having the coolant flowing through the cooling plate  412  causes the temperature of the cooling plate  412  to be less than the temperature of the exhaust entering the exhaust cooling apparatus  117 . The exhaust entering the exhaust cooling apparatus  117  is cooled by the cooling plate  412 , and cooled surfaces of the cooling plate  412  also condense solid particles in the exhaust, preventing solid by-product materials from exiting the exhaust cooling apparatus  117  and reaching pumps and facility exhaust  196 . In one embodiment, the cooling plate  412  does not include the channel for a coolant to flow therethrough, and the temperature of the surfaces of the cooling plate  412  is low enough to cool the exhaust and to condense solid particles in the exhaust. 
         [0038]    The particles accumulated on the cooling plate  412  may fall into the collection device  410  by gravity. The collection device  410  includes a wall  418  and a bottom  420 . The bottom  420  is disposed below the cooling plate  412  such that the particles accumulated on the cooling plate  412  fall onto the bottom  420  of the collection device  410  by gravity. In other words, the bottom  420  may be located downstream of the cooling plate  412  with respect to gravity. The wall  418  may be cylindrical, as shown in  FIG. 4 , and a portion of the cooling plate  412  may extend into an opening  422  defined by the wall  418 . The collection device  410  may be removably coupled to the wall  408  in order to conveniently remove particles in the collection device  410 . The pressure inside the exhaust cooling apparatus  117  during operation is monitored by a pressure sensor  416 . The pressure sensor  416  may be coupled to the end  414 , as shown in  FIG. 4 . 
         [0039]      FIG. 5  is a cross-sectional view of the exhaust cooling apparatus  117  according to one embodiment described herein. As shown in  FIG. 5 , the exhaust cooling apparatus  117  includes a body  502  having an inlet  504 , an outlet  506 , a first end  507 , a second end  509  opposite the first end  507 , and a wall  508  between the inlet  504  and the outlet  506  and between the first end  507  and the second end  509 . The second end  509  may be removably coupled to the wall  508 . The wall  508  may be cylindrical, as shown in  FIG. 5 . The exhaust cooling apparatus  117  may include a first liner  510  adjacent to the inlet  504 , a second liner  512  adjacent to the outlet  506 , and a cooling plate  514  disposed between the first liner  510  and the second liner  512 . The first liner  510 , the second liner  512 , and the cooling plate  514  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. The cooling plate  514  may be coupled to the first end  507 . The first liner  510  may be coupled to the second end  509  and the second liner  512  may be coupled to the second end  509 . The cooling plate  514  may include a plurality of through holes  516 . The cooling plate  514  may be the same as the cooling plate  314  shown in  FIG. 3 . 
         [0040]    In order to trap particles in the exhaust cooling apparatus  117 , a device is utilized to introduce turbulence to the exhaust flowing within the exhaust cooling apparatus  117  adjacent a cooled structure with high conductance to prevent a pressure increase in exhaust cooling apparatus  117 . The cooled structure with high conductance may be the cooling plate  514 , and the device may be a device  518  disposed on a plate  519 . The plate  519  and the device  518  may be part of the first liner  510 . The plate  519  may be substantially parallel to the cooling plate  514 . The plate  519  may include a first portion  522  defined by the device  518  and a second portion  524  having a plurality of through holes  526 . Each through hole  526  is aligned with a corresponding through hole  516  of the cooling plate  514 . 
         [0041]    The device  518  may include a wall  532 , a first end  534 , and a second end  536 . The first end  534  device  518  may be adjacent or coupled to the inlet  504 , and the second end  536  may be coupled to the plate  519  to define the first portion  522 . The first portion  522  does not include any through holes. In one embodiment, the wall  532  is cylindrical, i.e., the wall  532  form an angle A 4  with respect to the first portion  522  of the plate  519 , and the angle A 4  is about 90 degrees. In another embodiment, the angle A 4  is an acute angle, as shown in  FIG. 5 . In another embodiment, the angle A 4  is an obtuse angle. The first end  534  of the device  518  may include a top portion  544  having a curved side profile, as shown in  FIG. 5 . The curved side profile of the top portion  544  may include both concave and convex side profiles. The device  518  may further include a plurality of slit openings  520  in the wall  532  at the first end  534 . The slit openings  520  may be located on the wall  532  from the first end  534  up to the center of the wall  532 , and the center of the wall  532  is defined as the center point between the first end  534  and the second end  536 . 
         [0042]    The second liner  512  may include a device  528  having a wall  538 , a first end  540 , and a second end  542 . The wall  538  may be cylindrical, as shown in  FIG. 5 . The first end  540  may be adjacent to the cooling plate  514 , and the second end  542  may be adjacent or coupled to the outlet  506 . A plurality of slit openings  530  may be formed in the wall  538 . The slit openings  530  may be located on the wall  538  from the first end  540  up to the center of the wall  538 , and the center of the wall  538  is defined as the center point between the first end  540  and the second end  542 . 
         [0043]    During operation, exhaust exiting the plasma source  100  ( FIG. 1 ) enters the exhaust cooling apparatus  117  via the inlet  504 . The exhaust enters a region  546  surrounded by the device  518 . The flow of the exhaust becomes turbulent as the exhaust comes into contact with the second portion  522  of the plate  519 , causing particles to drop out of the exhaust. The exhaust exits the region  546  via the plurality of slit openings  520 , and the slit openings  520  can block particles remained in the exhaust from exiting the region  546 . Particles dropped out of the exhaust and blocked by the slit openings  520  may fall onto the second portion  522  of the plate  519 . The exhaust then flows through the through holes  526  in the plate  519  and the through holes  516  in the cooling plate  514 , and particles may condense and fall onto the second liner  512  as the temperature of the exhaust is reduced by the cooling plate  514 . The exhaust then enters a region  550  defined by the device  528  through the plurality of slit openings  530 , and the slit openings  530  can further reduce particles remained in the exhaust. The second end  509 , along with the first liner  510  and the second liner  512 , may be pulled out of the exhaust cooling apparatus  117  in order to remove the particles collected on first and second liners  510 ,  512 . The pressure inside the exhaust cooling apparatus  117  during operation is monitored by a pressure sensor  513 . The pressure sensor  513  may be coupled to the second end  509 , as shown in  FIG. 5 . An injection port (not shown) may be formed in the second end  509  for injecting a reagent or diluent into the exhaust cooling apparatus  117 . 
         [0044]      FIG. 6  is a cross-sectional view of the exhaust cooling apparatus  117  according to one embodiment described herein. As shown in  FIG. 6 , the exhaust cooling apparatus  117  includes a body  602  having an inlet  604 , an outlet  606 , a first end  607 , a second end  609  opposite the first end  607 , and a wall  608  between the inlet  604  and the outlet  606  and between the first end  607  and the second end  609 . The second end  609  may be removably coupled to the wall  608 . The wall  608  may be cylindrical, as shown in FIG.  6 . The exhaust cooling apparatus  117  may include a first liner  610  adjacent to the inlet  604 , a second liner  612  adjacent to the outlet  606 , and a cooling plate  614  disposed between the first liner  610  and the second liner  612 . The first liner  610 , the second liner  612 , and the cooling plate  614  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. The cooling plate  614  may be coupled to the first end  607 . The first liner  610  may be coupled to the second end  609  and the second liner  612  may be coupled to the second end  609 . The cooling plate  614  may include a plurality of through holes  616 . The cooling plate  614  may be the same as the cooling plate  314  shown in  FIG. 3 . 
         [0045]    In order to trap particles in the exhaust cooling apparatus  117 , a device is utilized to introduce turbulence to the exhaust flowing within the exhaust cooling apparatus  117  adjacent a cooled structure with high conductance to prevent a pressure increase in exhaust cooling apparatus  117 . The cooled structure with high conductance may be the cooling plate  614 , and the device may be a device  618  disposed on a plate  619 . The plate  619  and the device  618  may be part of the first liner  610 .  FIG. 7A  is a perspective view of a portion of the first liner  610  according to one embodiment described herein. The plate  619  may be substantially parallel to the cooling plate  614 . The plate  619  may include a first portion  622  defined by the device  618  and a second portion  624  having a plurality of through holes  626 . Each through hole  626  may be aligned with a corresponding through hole  616  of the cooling plate  614 . The device  618  may include a wall  632 , a first end  634 , and a second end  636 . 
         [0046]    Referring back to  FIG. 6 , the first end  634  of the device  618  may be spaced apart from the inlet  604  by a distance  637 . The second end  536  may be coupled to the plate  619  to define the first portion  622  of the plate  619 . The first portion  622  does not include any through holes. In one embodiment, the wall  632  is cylindrical, i.e., the wall  632  forms an angle A 5  with respect to the first portion  622  of the plate  619 , and the angle A 5  is about 90 degrees. In another embodiment, the angle A 5  is an acute angle, as shown in  FIG. 6 . In another embodiment, the angle A 5  is an obtuse angle. The first end  634  of the device  618  may include a top portion  644  having a curved side profile, as shown in  FIG. 6 . The curved side profile of the top portion  644  may include both concave and convex side profiles. 
         [0047]    The second liner  612  may include a device  628  having a wall  638 , a first end  640 , and a second end  642 , as shown in  FIG. 7B . The wall  638  may be cylindrical, as shown in  FIG. 7B . Referring back to  FIG. 6 , the first end  640  may be spaced apart from the cooling plate  514  by a distance  641 , and the second end  642  may be adjacent or coupled to the outlet  606 . 
         [0048]    During operation, exhaust exiting the plasma source  100  ( FIG. 1 ) enters the exhaust cooling apparatus  117  via the inlet  604 . The exhaust enters a region  646  surrounded by the device  618 . The flow of the exhaust becomes turbulent as the exhaust comes into contact with the second portion  622  of the plate  619 , causing particles to drop out of the exhaust. The exhaust exits the region  646  via the space between the inlet  604  and the first end  634  of the device  618 . Particles dropped out of the exhaust may fall onto the second portion  622  of the plate  619 . The exhaust then flows through the through holes  626  in the plate  619  and the through holes  616  in the cooling plate  614 , and particles may condense and fall onto the second liner  612  as the temperature of the exhaust is reduced by the cooling plate  614 . The exhaust then enters a region  650  defined by the device  628  through the space between the cooling plate  614  and the first end  640  of the device  628 . The second end  609 , along with the first liner  610  and the second liner  612 , may be pulled out of the exhaust cooling apparatus  117  in order to remove the particles collected on first and second liners  610 ,  612 . The pressure inside the exhaust cooling apparatus  117  during operation is monitored by a pressure sensor  613 . The pressure sensor  613  may be coupled to the second end  609 , as shown in  FIG. 6 . An injection port (not shown) may be formed in the second end  509  for injecting a reagent or diluent into the exhaust cooling apparatus  117 . 
         [0049]      FIG. 8  is a cross-sectional view of the exhaust cooling apparatus  117  according to one embodiment described herein. As shown in  FIG. 8 , the exhaust cooling apparatus  117  includes a body  802  having an inlet  804 , an outlet  806 , a first end  807 , a second end  809  opposite the first end  807 , and a wall  808  between the inlet  804  and the outlet  806  and between the first end  807  and the second end  809 . The second end  809  may be removably coupled to the wall  808 . The wall  808  may be cylindrical, as shown in  FIG. 8 . The exhaust cooling apparatus  117  may include a first liner  810  adjacent to the inlet  804 , a second liner  812  adjacent to the outlet  806 , and a cooling plate  814  disposed between the first liner  810  and the second liner  812 . The first liner  810 , the second liner  812 , and the cooling plate  814  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. The cooling plate  814  may be coupled to the first end  807 . The first liner  810  may be coupled to the second end  809  and the second liner  812  may be coupled to the second end  809 . The cooling plate  814  may include a plurality of through holes  816 . The cooling plate  814  may be the same as the cooling plate  314  shown in  FIG. 3 . 
         [0050]    In order to trap particles in the exhaust cooling apparatus  117 , a device is utilized to introduce turbulence to the exhaust flowing within the exhaust cooling apparatus  117  adjacent a cooled structure with high conductance to prevent a pressure increase in exhaust cooling apparatus  117 . The cooled structure with high conductance may be the cooling plate  814 , and the device may be a device  818 . The device  818  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. The device  818  may include a body  819  including a first end  830  and a second end  834 . The body  819  may be cylindrical, as shown in  FIG. 8 . The first end  830  may be coupled to a flange  832 , and the flange  832  may be rested on a flange  820  of the inlet  804 . The flange  832  may be utilized to couple to the plasma source  100  ( FIG. 1 ). The second end  834  may extend into the wall  808  of the exhaust cooling apparatus  117  to a location above the cooling plate  814 . 
         [0051]    The device  818  may also include a diffuser  824  disposed within the body  819 . The diffuser  824  may include a plurality of blades  826  coupled to a cone  828 . The plurality of blades  826  may be located at the first end  830  of the body  819 , and each blade  826  may be tilted with respect to the vertical in order to introduce turbulence to the exhaust entering the exhaust cooling apparatus  117 . In one embodiment, each blade  826  is titled at about 45 degrees with respect to the vertical. The number of blades  826  may vary. In one embodiment, there are 10 blades  826 . Disposed below the blades  826  is the cone  828 . The cone  828  includes a first end  836  coupled to the blades  826  and a second end  838  opposite the first end  836 . The second end  838  has a diameter  840  that is greater than a diameter of the first end  836 . A hollow cylinder  842  may be disposed below the cone  828 . The hollow cylinder  842  has a first end  843  and a second end  845  opposite the first end  843 . The hollow cylinder  842  has a diameter  844  that is less than the diameter  840  of the second end  838  of the cone  828 . The first end  843  of the hollow cylinder  842  may be level with the second end  838  of the cone  828 , and a gap  841  may be formed between the first end  843  of the hollow cylinder  842  and the second end  838  of the cone  828  due to the different in diameters. 
         [0052]    The second end  834  of the body  819  may be coupled to a bottom  846 , and the bottom  846  may be coupled to the second end  845  of the hollow cylinder  842 . In one embodiment, the bottom  846  is annular. A plurality of fins  848  may be coupled to the body  819 . The fins  848  may be disposed over the bottom  846  or coupled to the bottom  846 . Each fin  848  may include a top portion  850 , and the top portion  850  may form an angle A 6  with respect to the body  819 . The angle A 6  may be an acute angle. The number of fins  848  coupled to the body  819  may vary. In one embodiment, there are six fins  848  coupled to the body  819 . 
         [0053]    During operation, exhaust exiting the plasma source  100  ( FIG. 1 ) enters the exhaust cooling apparatus  117  via the inlet  804 . The exhaust becomes turbulent as the exhaust is entering the exhaust cooling apparatus  117  at an angle with respect to the vertical by the plurality of blades  826 , causing particles to drop out of the exhaust. Particles dropping out of the exhaust may fall onto the bottom  846 . The plurality of fins  848  can slow down particles falling onto the bottom  846 . The exhaust enters the hollow cylinder  842  via the gap  841  and then flows through the through holes  816  in the cooling plate  814 . Particles may condense and fall onto the second liner  812  as the temperature of the exhaust is reduced by the cooling plate  814 . The exhaust then exits the exhaust cooling apparatus  117  via the outlet  806 . The device  818  may be removable from the exhaust cooling apparatus  117  in order to remove the particles collected on the bottom  846  of the device  818 . The second end  809 , along with the first liner  810  and the second liner  812 , may be pulled out of the exhaust cooling apparatus  117  in order to remove the particles collected on first and second liners  810 ,  812 . The pressure inside the exhaust cooling apparatus  117  during operation is monitored by a pressure sensor  813 . The pressure sensor  813  may be coupled to the second end  809 , as shown in  FIG. 8 . An injection port (not shown) may be formed in the second end  809  for injecting a reagent or diluent into the exhaust cooling apparatus  117 . 
         [0054]      FIG. 9  is a cross-sectional view of the exhaust cooling apparatus  117  according to one embodiment described herein. As shown in  FIG. 9 , the exhaust cooling apparatus  117  includes a body  902  having an inlet  904 , an outlet  906 , a first end  907 , a second end  909  opposite the first end  907 , and a wall  908  between the inlet  904  and the outlet  906  and between the first end  907  and the second end  909 . The second end  909  may be removably coupled to the wall  808 . The wall  908  may be cylindrical, as shown in  FIG. 9 . The exhaust cooling apparatus  117  may include a first liner  910  adjacent to the inlet  904 , a second liner  912  adjacent to the outlet  906 , and a cooling plate  914  disposed between the first liner  910  and the second liner  912 . The first liner  910 , the second liner  912 , and the cooling plate  914  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. The cooling plate  914  may be coupled to the first end  907 . The first liner  910  may be coupled to the second end  909  and the second liner  912  may be coupled to the second end  909 . The cooling plate  914  may include a plurality of through holes  916 . The cooling plate  914  may be the same as the cooling plate  314  shown in  FIG. 3 . 
         [0055]    In order to trap particles in the exhaust cooling apparatus  117 , a device is utilized to introduce turbulence to the exhaust flowing within the exhaust cooling apparatus  117  adjacent a cooled structure with high conductance to prevent a pressure increase in exhaust cooling apparatus  117 . The cooled structure with high conductance may be the cooling plate  814 , and the device may be a device  918 . The device  918  may be made of stainless steel, aluminum, nickel coated aluminum, or any suitable material. The device  918  may include a body  919  including a first end  920  and a second end  924 . The body  919  may be cylindrical, as shown in  FIG. 9 . The first end  920  may be disposed below the inlet  904 , and the first end  920  may be coupled to a flange  922 . The second end  924  may extend into the wall  908  of the exhaust cooling apparatus  117  to a location below the cooling plate  914 . 
         [0056]    The device  918  may include a diffuser  925  disposed at the first end  920  of the body  919 . The diffuser  925  may include a flange  927  coupled to the flange  922 . A ring  921  may be disposed on the flange  927  and may extend to the inlet  904 . The diffuser  925  may include a plurality of blades  926  coupled to a center  929 . The plurality of blades  926  may be the same as the plurality of blades  826  shown in  FIG. 8 . A plurality of openings  928  may be formed in the body  919 . The openings  928  may be circular, as shown in  FIG. 9 , or any other suitable shape. A bottom may be coupled to the second end  924  of the body  919 . In one embodiment, the bottom  930  is circular. A plurality of fins  932  may be coupled to the body  919 . The fins  932  may be disposed over the bottom  930  or coupled to the bottom  930 , as shown in  FIG. 9 . The plurality of fins  932  may be the same as the plurality of fins  848  shown in  FIG. 8 . A flange  934  may be coupled to the body  919 , and the flange  934  may rest on the cooling plate  914 . 
         [0057]    During operation, exhaust exiting the plasma source  100  ( FIG. 1 ) enters the exhaust cooling apparatus  117  via the inlet  904 . The exhaust becomes turbulent as the exhaust is entering the exhaust cooling apparatus  117  at an angle with respect to the vertical by the plurality of blades  926 , causing particles to drop out of the exhaust. Particles dropping out of the exhaust may fall onto the bottom  930 . The plurality of fins  932  can slow down particles falling onto the bottom  930 . The exhaust exits the device  918  via the plurality of openings  928  and then flows through the through holes  916  in the cooling plate  914 . Particles may condense and fall onto the second liner  912  as the temperature of the exhaust is reduced by the cooling plate  914 . The exhaust then exits the exhaust cooling apparatus  117  via the outlet  906 . The device  918  may be removable from the exhaust cooling apparatus  117  in order to remove the particles collected on the bottom  930  of the device  918 . The second end  909 , along with the first liner  910  and the second liner  912 , may be pulled out of the exhaust cooling apparatus  117  in order to remove the particles collected on first and second liners  910 ,  912 . The pressure inside the exhaust cooling apparatus  117  during operation is monitored by a pressure sensor  913 . The pressure sensor  913  may be coupled to the second end  909 , as shown in  FIG. 9 . An injection port (not shown) may be formed in the second end  909  for injecting a reagent or diluent into the exhaust cooling apparatus  117 . 
         [0058]    While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.