Patent Publication Number: US-2022234069-A1

Title: Apparatus for processing substrate

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0011699, filed on Jan. 27, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     The inventive concept relates to an apparatus for processing a substrate, and more particularly, to an apparatus for processing a substrate including a processing container assembly. 
     DISCUSSION OF THE RELATED ART 
     Spin coating is a process that is used to deposit thin films of material, such as insulating layers or photoresist layers, onto a flat substrate, such as a wafer. A coating apparatus such as a spin coater may be used in the spin coating process. 
     In general, the coating apparatus includes a chuck, on which a substrate is mounted, a supplier for supplying a processing liquid to the substrate, and a process container in which a waste liquid such as a processing liquid is collected. Often, the processing liquid contains a volatile solvent mixed with the deposit material, or is volatile itself. For example, when the photoresist layer is formed on the substrate by using the coating apparatus, fumes may be generated in a gaseous state. These fumes are then discharged through an exhaust pipe connected to the process container. However, excess liquid or contaminants may enter the exhaust pipe, and when the contaminants are accumulated in the exhaust pipe, the exhaust pressure may abnormally change, causing reduced reliability of the coating apparatus and degradation of the coating process. 
     SUMMARY 
     The inventive concepts put forth in the present disclosure provide an apparatus for processing a substrate. 
     According to an aspect of the inventive concept, an apparatus for processing a substrate includes a mount, a processing liquid supply nozzle configured to provide a processing liquid to the substrate, a discharge container including a base plate including a liquid outlet and an exhaust port, an inner wall disposed on an inner circumference of the base plate and extending vertically, an outer wall disposed on an outer circumference of the base plate and extending vertically, and a barrier disposed on the base plate, wherein the barrier separates a first space connected to the liquid outlet from a second space connected to the exhaust port, an inner cover configured to guide a processing liquid from the substrate to the first space of the discharge container, wherein the inner cover includes a first guide plate that covers the second space of the discharge container, and further includes a second guide plate provided between the outer wall and the barrier of the discharge container, a flow guide mounted in the first space of the discharge container, a liquid collecting pipe connected to the liquid outlet of the discharge container, and an exhaust pipe connected to the exhaust port of the discharge container. 
     According to another aspect of the inventive concept, an apparatus for processing a substrate includes a mount and including a rotation shaft and a spin chuck disposed on the rotation shaft, a processing liquid supply nozzle configured to provide a processing liquid to the substrate supported by the mount, a discharge container on a lower portion of the spin chuck and including a base plate including a liquid outlet and an exhaust port, an inner wall arranged on the base plate to surround the rotation shaft, a barrier arranged on the base plate to surround the inner wall, an outer wall arranged on the base plate to surround the barrier, a first space located between the outer wall and the barrier and connected to the liquid outlet, and a second space located between the inner wall and the barrier and connected to the exhaust port, an inner cover including a first guide plate covering the second space of the discharge container and a second guide plate extending to an inside of the first space of the discharge container from an edge of the first guide plate, an outer cover extending upwards from an upper portion of the outer wall of the discharge container and at least partially surrounding the spin chuck, a flow guide arranged in the first space and including a guide main body at least partially surrounding the outer wall of the discharge container, a plurality of protrusions protruding from a lower portion of the guide main body, and a hook structure hooked to an upper portion of the barrier, a liquid collecting pipe coupled to the liquid outlet of the discharge container, an exhaust pipe coupled to the exhaust port of the discharge container, and a cleaning nozzle configured to spray a cleaning liquid to an inside of the discharge container. 
     According to another aspect of the inventive concept, an apparatus for processing a substrate includes a mount configured to support the substrate, a processing liquid supply nozzle configured to provide a processing liquid to the substrate supported by the mount, a discharge container including a base plate including a liquid outlet and an exhaust port, and a barrier disposed on the base plate and extending in a vertical direction to separate a first space connected to the liquid outlet from a second space connected to the exhaust port, an inner cover configured to guide the processing liquid from the substrate supported by the mount to the first space of the discharge container, and a flow guide mounted in the first space of the discharge container, wherein the flow guide includes a guide main body having a ring shape, a plurality of protrusions protruding from the guide main body and configured to guide a fluid into the first space, and a flow groove provided between adjacent protrusions of the plurality of protrusions and configured to allow fluid to pass therethrough. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects and features of the present disclosure will become more apparent by describing in detail example embodiments thereof with reference to the attached drawings, in which: 
         FIG. 1  is a cross-sectional view of an apparatus for processing a substrate according to example embodiments; 
         FIG. 2  is a perspective view of a flow guide included in the apparatus of  FIG. 1 ; 
         FIG. 3  is a side cut-away view of a flow guide included in the apparatus of  FIG. 1 ; 
         FIG. 4  is a schematic cross-sectional view of a process container assembly of  FIG. 1 , used for explaining flows of a liquid and a gas moving in the process container assembly; 
         FIG. 5  is a perspective view that illustrates a state in which a flow guide is mounted on a discharge container, according to example embodiments; 
         FIG. 6  is a perspective view that illustrates a state in which a flow guide is mounted on a discharge container, according to example embodiments; 
         FIG. 7  is a cross-sectional view that illustrates a state in which a flow guide is mounted on a discharge container, according to example embodiments; and 
         FIG. 8  is a perspective view of a flow guide according to example embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, one or more embodiments of the inventive concept will be described in detail with reference to the attached drawings. Like reference symbols in the drawings may denote like elements, and to the extent that a description of an element has been omitted, it may be understood that the element is at least similar to corresponding elements that are described elsewhere in the specification. Additionally, description of a singular element may apply to a plurality of the same elements, unless the context of the description or referenced drawings indicates otherwise. 
       FIG. 1  is a cross-sectional view of an apparatus  100  for processing a substrate according to example embodiments.  FIG. 2  is a perspective view of a flow guide  170  included in the apparatus  100  of  FIG. 1 .  FIG. 3  is a side cut-away view of the flow guide  170  included in the apparatus  100  of  FIG. 1 . 
     Referring to  FIGS. 1 to 3 , the apparatus  100  may provide a processing liquid to a substrate W to process the substrate W. For example, the apparatus  100  may form a material layer on the substrate W from the processing liquid. 
     As used herein, the term “substrate W” may indicate the substrate W itself or a stack structure including on or more layers, films, or the like formed on a surface of the substrate W. Also, the expression “the surface of the substrate W” may indicate an exposed surface of the substrate W itself or an exposed surface of a layer which is formed on the substrate W. For example, the substrate W may be a wafer or may include a wafer and at least one material layer formed on the wafer. The material layer may include an insulating layer, a polymer layer, and/or a photoresist layer, and the like formed on the wafer. 
     In example embodiments, the apparatus  100  for processing a substrate may form, on the substrate W, a photosensitive material layer such as a photoresist layer. For example, the apparatus  100  for processing a substrate may form a photosensitive material layer such as a photoresist layer on the substrate W by performing the spin coating process. 
     The apparatus  100  may include a chamber  111 , a substrate support  130 , a process container assembly  120 , a processing liquid supply nozzle  141 , and a cleaning nozzle  151 . 
     The chamber  111  includes an internal space  113  where the substrate W may be processed. In example embodiments, vacuum pressure or atmospheric pressure may be generated in the internal space  113  of the chamber  111 . The chamber  111  may include an opening. Through the opening of the chamber  111 , the substrate W may be disposed in or discharged from the internal space  113  of the chamber  111 . The opening of the chamber  111  may be sealed as needed to separate the internal space  113  of the chamber  111  from an external environment. 
     On an upper wall of the chamber  111 , a fan unit  115  may be installed. For example, the fan unit  115  may include a blower fan. The fan unit  115  may provide a clean gas which flows from the top to bottom of the chamber  111 . An exhaust portion  117  may be arranged on the bottom of the chamber  111  to exhaust the gas from the chamber  111 . The exhaust portion  117  may be connected to an exhaust device such as a vacuum pipe and may be configured to exhaust the gas from the chamber  111 . A descending air current may be formed in the chamber  111  by the fan unit  115  and the exhaust portion  117 . 
     The process container assembly  120  may be arranged in the internal space  113  of the chamber  111 . The process container assembly  120  may have an opening formed in an upper portion thereof. The process container assembly  120  may have a process space  129  in which the substrate support  130  and the substrate W mounted on the substrate support  130  may be accommodated. 
     The substrate support  130  may be arranged in the process space  129  of the process container assembly  120 . The substrate support  130  may include a spin chuck  131  and a rotation shaft  133 . The spin chuck  131  and the rotation shaft  133  may constitute a mount that is responsible for supporting and rotating the substrate W. 
     The spin chuck  131  may include a mounting surface on which the substrate W can be mounted. The spin chuck  131  may support the substrate W disposed on the mounting surface of the spin chuck  131 . In example embodiments, the spin chuck  131  may support the substrate W through vacuum suction of the substrate W. In example embodiments, the spin chuck  131  may support the substrate W by using an electrostatic force. The rotation shaft  133  may be rotated by an actuator, such as a rotation motor, relative a central axis. The spin chuck  131  may be coupled to the rotation shaft  133  and rotated according to the rotation of the rotation shaft  133 . The spin chuck  131  may be elevated in a vertical direction, for example, by the rotation shaft  133 . 
     The processing liquid supply nozzle  141  may supply a processing liquid to the substrate W. The processing liquid supply nozzle  141  may be arranged over the mounting surface of the substrate support  130 . The processing liquid supply nozzle  141  may be coupled to a nozzle arm  145  and a processing liquid source  143 , and may include a flow path in the nozzle arm  145 . The processing liquid supply nozzle  141  may receive the processing liquid supplied from the processing liquid source  143  through the flow path of the nozzle arm  145 . The processing liquid supply nozzle  141  may be moved by the nozzle arm  145 . For example, the processing liquid supply nozzle  141  may be moved between a spray position, where the processing liquid is sprayed onto the substrate W, and a waiting position, where the processing liquid supply nozzle  141  is spaced apart from the spray position. 
     In example embodiments, the processing liquid supply nozzle  141  may supply a photosensitive material such as photoresist to the substrate W. For example, while the spin chuck  131  is rotated and the substrate W is supported thereon, the processing liquid supply nozzle  141  may supply liquid photoresist to the center of the substrate W. Because the spin chuck  131  is rotated, the photoresist supplied to the substrate W may be moved in an outward radial direction of the substrate W because of a centrifugal force, and the photoresist may be evenly spread on the entire surface of the substrate W accordingly. 
     In some example embodiments, the apparatus  100  may further include nozzles for supplying other materials than the processing liquid which is supplied through the processing liquid supply nozzle  141 . For example, the apparatus  100  may further include a nozzle for supplying a solvent used during an Edge Bead Removal (EBR) process. When the photoresist layer is formed on the substrate W according to a spin coating method, the thickness of the photoresist layer at an edge portion of the substrate W may be relatively large. That is, a thickness of the photoresist layer coated on a center portion of the substrate W may lesser than the thickness of the photoresist layer coated on the edge portion of the substrate W. In this case, the nozzle may supply a solvent to the edge portion of the substrate W, and thus, the photoresist layer on the edge portion of the substrate W may be partially removed. 
     The cleaning nozzle  151  may supply a cleaning liquid to the process space  129  of the process container assembly  120 . The cleaning nozzle  151  may spray a cleaning liquid to the inside of the process container assembly  120  to remove contaminants that remain in the process container assembly  120 . For example, the cleaning nozzle  151  may receive the cleaning liquid for removing the contaminants in the process container assembly  120  from a cleaning liquid source, and may spray the cleaning liquid to the inside of the process container assembly  120 . Examples of the cleaning liquid may include a thinner, a solvent such as acetone, and the like. 
     The cleaning nozzle  151  may be arranged in the process container assembly  120 . For example, the cleaning nozzle  151  may be arranged under the spin chuck  131  and may spray the cleaning liquid to a rear surface of the substrate W and/or to the inside of the process container assembly  120 . Although  FIG. 1  illustrates that the process container assembly  120  may include two cleaning nozzles  151  therein, the present disclosure is not necessarily limited thereto and the process container assembly  120  may include one cleaning nozzle  151  or three or more cleaning nozzles  151 . 
     The process container assembly  120  may collect and discharge a waste liquid. For example, while the substrate W is processed according to the supply of the processing liquid to the substrate W, the processing liquid may flow from the substrate W and fall into the process container assembly  120 . Such a waste liquid may be collected in the process container assembly  120 , and the collected waste liquid may be discharged to the outside of the process container assembly  120 . 
     The process container assembly  120  may include a discharge container  180 , an outer cover  121 , an inner cover  123 , and the flow guide  170 . 
     With reference to  FIG. 1 , the discharge container  180  may be arranged under the spin chuck  131  and may include a hollow portion in which the rotation shaft  133  may be accommodated. The discharge container  180  may include a liquid accommodating space where the waste liquid may be collected. The discharge container  180  may include a liquid outlet  188  connected to the liquid accommodating space and configured to discharge the waste liquid. The liquid outlet  188  may be connected to a liquid collecting pipe  161 , and the waste liquid collected in the discharge container  180  may be discharged to the liquid collecting pipe  161  through the liquid outlet  188 . The discharge container  180  may additionally include a discharge space separated or distinguished from the liquid accommodating space, and may include an exhaust port  189  which is connected to the discharge space and configured to vent the gas. The exhaust port  189  may be connected to an exhaust pipe  163 , and the exhaust pipe  163  may be connected to an exhaust pump  165 . The exhaust pump  165  may inhale a gas from the discharge container  180  through the exhaust pipe  163  and may discharge the gas from the discharge container  180  through the exhaust pipe  163 . For example, a gas, which flows into the discharge container  180 , along with a liquid such as the processing liquid, may be discharged to the outside through the exhaust pipe  163 . In example embodiments, a plurality of exhaust pipes  163 , for example, two or three exhaust pipes  163 , may be connected to the discharge container  180 . 
     The discharge container  180  may include a base plate  181 , an inner wall  182 , an outer wall  183 , and a barrier  184 . 
     The base plate  181  may include the liquid outlet  188  and the exhaust port  189 . The inner wall  182 , the outer wall  183 , and the barrier  184  may be disposed on the base plate  181 , and extend in a vertical direction. The inner wall  182  may be adjacent to an inner circumference of the base plate  181  and may extend upwards from the base plate  181 . The outer wall  183  may be adjacent to an outer circumference of the base plate  181  and may extend upwards from the base plate  181 . The barrier  184  may be arranged between the outer wall  183  and the inner wall  182 , and may extend upwards from the base plate  181 . The barrier  184  may be arranged between the outer wall  183  and the inner wall  182  and may separate or distinguish a first space  191 , which is between the barrier  184  and the outer wall  183 , from a second space  192 , which is between the barrier  184  and the inner wall  182 . 
     The inner wall  182 , the outer wall  183 , and the barrier  184  may each have a ring shape in a plan view. In a plan view, the inner wall  182  may extend on the base plate  181  to horizontally surround the rotation shaft  133  of the substrate support  130 , the barrier  184  may extend on the base plate  181  to horizontally surround the inner wall  182 , and the outer wall  183  may extend on the base plate  181  to horizontally surround the barrier  184 . 
     The first space  191  of the discharge container  180  may be defined by the barrier  184 , the outer wall  183 , and the base plate  181 . The first space  191  of the discharge container  180  may be the liquid accommodating space where the waste liquid is collected, and may be connected to the liquid outlet  188  included in the base plate  181 . The second space  192  of the discharge container  180  may be defined by the barrier  184 , the inner wall  182 , and the base plate  181 . The second space  192  of the discharge container  180  may be connected to the exhaust port  189  which is included in the base plate  181 . A descending air current may be formed in the second space  192  of the discharge container  180  by the exhaust pressure generated from the exhaust pump  165 . The gas flowing into the first space  191  of the discharge container  180  may be moved to the second space  192  over the barrier  184 , and then may be discharged to the exhaust pipe  163  through the exhaust port  189 . Because the second space  192  of the discharge container  180  is separated from the first space  191  of the discharge container  180  where the waste liquid is collected, the gas and liquid may be separated from each other in the discharge container  180  and discharged. 
     An inner cover  123  may be arranged under the spin chuck  131  and the substrate W supporting the spin chuck  131 . The inner cover  123  may be coupled to the discharge container  180 . The inner cover  123  may guide the processing liquid flowing from the substrate W towards the first space  191  of the discharge container  180 . 
     In example embodiments, the inner cover  123  may include a first guide plate  1231  which covers the second space  192  of the discharge container  180 , and a second guide plate  1233  which extends downwards towards the inside of the first space  191  of the discharge container  180  from an edge of the first guide plate  1231 . 
     The first guide plate  1231  may be connected to an upper portion of the inner wall  182  of the discharge container  180 . The first guide plate  1231  may extend outwards in a radial direction from the upper portion of the inner wall  182  of the discharge container  180 , and may cover the second space  192  of the discharge container  180 . The first guide plate  1231  may be spaced apart vertically from the barrier  184  of the discharge container  180 . 
     The second guide plate  1233  may extend downwards to a height lower than where the upper portion of the barrier  184  is disposed, and may be spaced apart from the base plate  181  in the vertical direction. The second guide plate  1233  may also have a ring shape in a plan view. The second guide plate  1233  may extend substantially in parallel with the barrier  184  in the first space  191  of the discharge container  180 . The second guide plate  1233  may horizontally surround the barrier  184 , and the outer wall  183  of the discharge container  180  may horizontally surround the second guide plate  1233 . The second guide plate  1233  may be arranged between the barrier  184  and the outer wall  183  of the discharge container  180 , and may separate a flow path between the second guide plate  1233  and the barrier  184  from a flow path between the second guide plate  1233  and the outer wall  183 . The second guide plate  1233  may extend downwards to the inside of the first space  191  of the discharge container  180  from the edge of the first guide plate  1231  and may form a curved flow path in the first space  191  of the discharge container  180 . 
     The processing liquid flowing from the substrate W may flow along the first guide plate  1231  and flow into the first space  191  of the discharge container  180  through the flow path formed between the second guide plate  1233  and the outer wall  183  of the discharge container  180 . 
     The outer cover  121  may be connected to an upper portion of the outer wall  183  of the discharge container  180 . A portion of outer cover  121  may have a cylindrical shape which surrounds the substrate W. The outer cover  121  may extend from the upper portion of the outer wall  183  of the discharge container  180  to a height greater than the height at which the substrate W is supported by the substrate support  130 . 
     In example embodiments, the outer cover  121  may include a vertical extending portion which extends from the upper portion of the outer wall  183  of the discharge container  180  in a vertical direction, and an inclined extending portion upwardly inclined and extending inwards from an upper portion of the vertical extending portion. For example, as seen in a cross sectional view of the outer cover  121 , the inclined extending portion of the outer cover  121  may form an angle towards a center region where the substrate W is disposed with respect to the vertical extending portion of the outer cover  121 . During operation of the apparatus  100 , the outer cover  121  may guide the processing liquid dispersed from the substrate W in the radial direction to the discharge container  180 . For example, after the processing liquid dispersed from the substrate Win the radial direction collides with the outer cover  121 , the processing liquid may flow into the first space  191  of the discharge container  180  along an inner surface of the outer cover  121 . The processing liquid moved to the discharge container  180  may be discharged to the liquid collecting pipe  161  through the liquid exhaust port  188  formed on the base plate  181 . 
     The flow guide  170  may be arranged between the barrier  184  and the outer wall  183  of the discharge container  180 . The flow guide  170  may be arranged in the first space  191  of the discharge container  180 , and may guide a flow of a fluid entering the discharge container  180 . The flow guide  170  may be obliquely arranged in the first space  191 ; this will be further described below. A portion of the flow guide  170  may partially block a flow path defined by the second guide plate  1233  of the inner cover  123  and the outer wall  183  of the discharge container  180 . For example, a portion of the flow guide  170  may be obliquely tilted towards the flow path below the downstream of the flow path defined by the second guide plate  1233  of the inner cover  123  and the outer wall  183  of the discharge container  180 . 
     The flow guide  170  may include a guide main body  171  which has a ring shape and protrusions  173  protruding from the bottom of the guide main body  171 . 
     The guide main body  171  may surround the barrier  184 . The guide main body  171  may have a cylindrical shape with a hollow center. 
     The protrusions  173  may be spaced apart from each other along a circumferential direction of the guide main body  171 . The protrusions  173  may extend in an outward normal direction from the guide main body  171 . The direction in which the protrusions  173  extend is different than the direction in which the guide main body  171  extends, and the direction in which the second guide plate  1233  of the inner cover  123  extends. For example, the protrusions  173  may protrude towards the outer wall  183  of the discharge container  180  from the bottom of the guide main body  171 . The protrusions  173  may be downwardly inclined and extend outwards from the bottom of the guide main body  171 . 
     Each protrusion  173  may have a tapered shape with a width that decreases along the outward extension of the protrusion  173  from the bottom of the guide main body  171 . For example, the width of a protrusion  173  may be defined as a length of a protrusion  173  in the circumferential direction, and may decrease from the base of the bottom of the guide main body  171  towards an outward direction. 
     Flow grooves  175  may be formed between neighboring protrusions  173  in the circumferential direction of the guide main body  171 . The width of a flow groove  175  may be defined as the empty space between the protrusions  173  along the circumferential direction, and the width of the flow groove  175  may increase towards ends of the protrusions  173 . For example, the width of the flow groove  175  in the circumferential direction may increase with distance away from the bottom of the guide main body  171 . 
     In example embodiments, the flow guide  170  may include a plastic material. For example, the flow guide  170  may include polypropylene, Teflon, or the like. 
     In example embodiments, the flow guide  170  may be formed by a plastic injection molding method. For example, the flow guide  170  may be formed according to an integral plastic injection molding method, and may entirely include the same material. For example, the guide main body  171 , the protrusions  173 , and a hook structure  177  forming the flow guide  170  may include the same materials. 
       FIG. 4  is a schematic cross-sectional view of the process container assembly of  FIG. 1 , used for explaining flows of a liquid and a gas moving in the process container assembly. 
     Referring to  FIGS. 1 to 4 , a gas may flow in the first space  191  of the discharge container  180  along with liquids such as the processing liquid and the cleaning liquid. A fluid which includes the liquids and the gas may flow in the first space  191  of the discharge container  180 . The liquids may be accommodated in the first space  191 , and the gas may flow from the first space  191  over the barrier  184  to the second space  192  which is further inside than the first space  191 . 
     For example, the liquids and the gas flowing into the discharge container  180  may be guided and flow to a surface of the flow guide  170  (e.g., an outer side surface of the guide main body  171  and/or an outer side surface of the protrusion  173 ) in a first flow direction Fl shown in 
       FIG. 4  and may flow inside the flow guide  170  through the flow groove  175  of the flow guide  170 . The liquid passing through the flow groove  175  of the flow guide  170  may be temporarily accommodated (e.g., held) in the first space  191  of the discharge container  180  and discharged to the outside through the liquid collecting pipe  161  in a second flow direction F 2  shown in  FIG. 4 . In addition, because the exhaust pressure (for example, a negative pressure) provided by the exhaust pump  165  is present in the second space  192 , the gas may flow to the second space  192  over the barrier  184  in a third flow direction F 3  shown in  FIG. 4  and may be discharged to the outside through the second space  192  and the exhaust pipe  163 . 
     In some conventional apparatuses, a waste liquid may be sucked into an exhaust pipe along an air current flowing to an exhaust port. When the waste liquid flows in the exhaust pipe, the exhaust pipe is contaminated, and the contamination of the exhaust pipe may cause an abnormal change in the exhaust pressure working in the exhaust pipe. 
     However, in the present embodiment, in the discharge container  180 , the first space  191  where the waste liquid is collected is separated from the second space  192  connected to the exhaust pipe  163  through which the gas is discharged. In the first space  191  of the discharge container  180 , the flow guide  170  which guides the flow of the liquid and gas flowing into the discharge container  180  is arranged. Because the flow guide  170  is arranged in the first space  191  of the discharge container  180 , a current of the gas flowing into the discharge container  180  is decelerated. Accordingly, the waste liquid may be prevented from being sucked into the second space  192  along the air current flowing to the second space  192  of the discharge container  180 , over the barrier  184 . Therefore, the contamination of the exhaust pipe  163  by the inflow of the waste liquid to the exhaust pipe  163  may be prevented, and a change in the exhaust pressure according to the contamination of the exhaust pipe  163  may be prevented. As a result, the reliability of a coating process using the apparatus  100  may be increased. 
     Also, in the present embodiment, because the flow guide  170  is arranged in the first space  191  of the discharge container  180 , the contaminants in the exhaust pipe  163  may be prevented from flowing backwards towards the inside of the process container assembly  120  and the substrate W supported by the substrate support  130 . Therefore, cleaning of equipment including the process container assembly  120 may be needed less often, and an equipment operation rate may be increased. 
       FIG. 5  is a perspective view of a state in which the flow guide  170  is mounted on the discharge container  180 , according to example embodiments. 
     Referring to  FIGS. 1 to 3 and 5 , the flow guide  170  may be suspended in the discharge container  180 . 
     In example embodiments, the flow guide  170  may include hook structures  177  on the upper portion of the guide main body  171 . The hook structures  177  are spaced apart from each other in the circumferential direction of the guide main body  171 . The number of hook structures  177  may be three as shown in  FIG. 2 , but the present disclosure is not necessarily limited thereto, and there may be two hook structures, or four or more. 
     The hook structures  177  of the flow guide  170  may be hooked to the upper portion of the barrier  184 . As the hook structures  177  are hooked to the upper portion of the barrier  184 , the flow guide  170  may be suspended in the discharge container  180  and fixed thereto. Because the flow guide  170  and the discharge container  180  may be assembled by hooking the hook structures  177  to the barrier  184  of the discharge container  180 , the process container assembly  120  may be easily assembled. 
       FIG. 6  is a perspective view that illustrates a state in which the flow guide  170  is mounted on the discharge container  180 , according to example embodiments. 
     Referring to  FIGS. 1 to 3 and 6 , the barrier  184  of the discharge container  180  may include locking grooves  1841  in which the hook structures  177  of the flow guide  170  may be inserted. The number of the locking grooves  1841  in the barrier  184  may match the number of the hook structures  177 . The locking grooves  1841  may be located along the circumference of the barrier  184  to correspond to the hook structures  177 . Because the hook structures  177  of the flow guide  170  are inserted into the locking grooves  1841  of the barrier  184 , the flow guide  170  may be rigidly fixed to the barrier  184 . 
       FIG. 7  is a cross-sectional view that illustrates a state in which the flow guide  170  is mounted on the discharge container  180 , according to example embodiments. 
     Referring to  FIGS. 1 to 3 and 7 , the protrusions  173  of the flow guide  170  may be in contact with an inner surface of the discharge container  180 . The protrusions  173  of the flow guide  170  may be supported by the inner surface of the discharge container  180 . As the protrusions  173  of the flow guide  170  are supported by the inner surface of the discharge container  180 , the flow guide  170  may be mounted on the discharge container  180 . In example embodiments, engaging portions  187  may be formed on the inner surface of the discharge container  180  and contact the protrusions  173  of the flow guide  170 . The engaging portions  187  may be wall extensions that are able to support the protrusions  173 . The protrusions  173  of the flow guide  170  may be engaged to the engaging portions  187  of the discharge container  180 . The protrusions  173  of the flow guide  170  may include projections  1731  which project outwards so that the protrusions  173  of the flow guide  170  may be engaged to the engaging portions  187  of the discharge container  180 . 
     In some example embodiments, the flow guide  170  may be fixed to the discharge container  180  because the protrusions  173  are supported to the inner surface of the discharge container  180  and the hook structures  177  are hooked to the upper portion of the barrier  184 . 
     In some example embodiments, the flow guide  170  may be fixed to the discharge container  180  by only the support of the protrusions  173  to the inner surface of the discharge container  180 , and the hook structures  177  of the flow guide  170  may be omitted. 
     The flow guide  170  may contact and support the second guide plate  1233  of the inner cover  123 . The guide main body  171  of the flow guide  170  may include a steps  178  at locations where the guide main body  171  contacts a lower portion of the second guide plate  1233  of the inner cover  123 . The step  178  of the flow guide  170  may be defined by a supporting surface which contacts and supports the lower end of the second guide plate  1233  of the inner cover  123  as well as an outer side surface of the flow guide  170  that extends upwards from the supporting surface. The outer side surface of the flow guide  170 , which extends upwards from the supporting surface of the flow guide  170 , may contact an inner side surface of the second guide plate  1233 . 
       FIG. 8  is a perspective view of a flow guide  170   a  according to example embodiments. 
     The flow guide  170   a  of  FIG. 8  may be similar to or identical to the flow guide  170  of  FIGS. 1 to 3  except in that the flow guide  170   a  further includes through holes  179 . 
     Referring to  FIGS. 1 to 3 and 8 , the flow guide  170   a  may include the through holes  179 . The through hole  179  may penetrate the guide main body  171  and/or the protrusion  173 . 
     For example, the flow guide  170   a  may include the through holes  179  arranged spaced apart from each other in a circumferential direction. The through holes  179  may allow a fluid flowing in the discharge container  180  to pass through the flow guide  170   a.    
     Because the through holes  179  are formed in the flow guide  170   a,  the fluid flowing in the discharge container  180  may pass the flow guide  170   a  through the flow grooves  175  as well as the through holes  179  between the protrusions  173 . The through holes  179  may adjust a rate of velocity reduction of an air current by the flow guide  170   a.  For example, by appropriately adjusting the size(s) and the number of through holes  179 , the rate of velocity reduction of the air current by the flow guide  170   a  may be adjusted. 
     While the inventive concept has been particularly shown and described with reference to embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims.