Abstract:
Provided is a substrate treating apparatus. The substrate treating apparatus according to embodiments of the present invention may include a cleaning chamber cleaning foreign objects on a substrate, and a recycling unit recycling by recovering a mixed solution including a first chemical and a second chemical used in cleaning of the substrate, wherein the recycling unit includes a separation unit separating the mixed solution recovered from the cleaning chamber, a recovery line connecting the separation unit and the cleaning chamber and allowing the mixed solution to flow into the separation unit, a decompression line having one end connected to the separation unit and exhausting the mixed solution evaporated from the separation unit, and a decompression unit installed in the decompression line and reducing pressure in the separation unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Application Nos. 10-2011-0111956, filed on Oct. 31, 2011, and 10-2011-0132108, filed on Dec. 9, 2011, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND 
       [0002]    The present invention disclosed herein relates to a substrate treating apparatus treating a substrate, and more particularly, to a substrate treating apparatus recycling chemicals used in cleaning of a substrate and a chemical recycling method. 
         [0003]    Various processes, such as photolithography, etching, ashing, ion implantation, and thin film deposition, are performed on a substrate in order to manufacture semiconductor devices or liquid crystal displays. In order to remove contaminants and particles generated in each process, a cleaning process cleaning the substrate is performed before or after performing the each process. 
         [0004]    In general, the cleaning process is performed through cleaning the substrate by providing chemicals to the substrate. Chemicals remove foreign objects adhered to the substrate and are then discarded by being discharged outside, or used chemicals are separated by using a difference between boiling points thereof and then recycled. Typically, used chemicals are separated by being heated at an atmospheric pressure. Therefore, since chemicals must be heated at high temperatures so as to allow the chemicals to reach their boiling points, the energy consumed for recycling the chemicals may be relatively large, and thus, efficiency may decrease. 
       SUMMARY 
       [0005]    The present invention provides a substrate treating apparatus recycling chemicals used in cleaning of a substrate and a chemical recycling method. 
         [0006]    The present invention also provides a substrate treating apparatus reducing time required for recycling chemicals and a chemical recycling method. 
         [0007]    The present invention also provides a substrate treating apparatus reducing costs required for recycling chemicals and a chemical recycling method. 
         [0008]    Embodiments of the present invention provide substrate treating apparatuses including: a cleaning chamber cleaning foreign objects on a substrate; and a recycling unit recycling by recovering a mixed solution including a first chemical and a second chemical used in cleaning of the substrate, wherein the recycling unit includes: a separation unit separating the mixed solution recovered from the cleaning chamber; a recovery line connecting the separation unit and the cleaning chamber and allowing the mixed solution to flow into the separation unit; a decompression line having one end connected to the separation unit and exhausting the mixed solution evaporated from the separation unit; and a decompression unit installed in the decompression line and reducing pressure in the separation unit. 
         [0009]    In other embodiments of the present invention, methods of recycling chemicals including: introducing a mixed solution include a first chemical and a second chemical used in cleaning of a substrate into a separation unit through a recovery line; exhausting gas and chemicals evaporated from the separation unit by using a decompression pump to heat the mixed solution in the separation unit in a decompressed state; and recovering the first chemical when purity of the first chemical remaining in the separation unit reaches a predetermined level. 
         [0010]    In still other embodiments of the present invention, substrate treating apparatuses include: a cleaning chamber cleaning foreign objects on a substrate with a mixed solution of sulfuric acid and hydrogen peroxide; a recovery line recovering the mixed solution used in cleaning of the substrate from the cleaning chamber; a separation unit separating the sulfuric acid by heating the mixed solution recovered; a decompression line discharging the mixed solution evaporated from the separation unit; and a decompression unit reducing pressure of the separation unit to decrease a boiling point of the mixed solution. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain principles of the present invention. In the drawings: 
           [0012]      FIG. 1  is a schematic diagram illustrating a substrate treating apparatus according to an embodiment of the present invention; 
           [0013]      FIG. 2  is a schematic diagram illustrating a substrate treating apparatus according to another embodiment of the present invention; 
           [0014]      FIG. 3  illustrates a configuration of a recycling unit; 
           [0015]      FIG. 4  illustrates a configuration of a separation unit according to an embodiment of the present invention; 
           [0016]      FIG. 5  illustrates a configuration of a separation unit according to another embodiment of the present invention; 
           [0017]      FIG. 6  illustrates a configuration of a condenser; and 
           [0018]      FIG. 7  illustrates a configuration of a preheating unit according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0019]    Hereinafter, embodiments of the present invention will be described in more detain with reference to the accompanying drawings,  FIGS. 1 through 7 . The present invention may, however, be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Therefore, shapes of the elements in the figures are exaggerated for clarity of illustration. 
         [0020]      FIG. 1  is a schematic diagram illustrating a substrate treating apparatus according to an embodiment of the present invention. 
         [0021]    Referring to  FIG. 1 , a substrate treating apparatus  1  includes a cleaning chamber  2 , a recycling unit  3 , and a chemical supply unit  6 . 
         [0022]    The chemical supply unit  6  is connected to the cleaning chamber  2  through a supply line  7 . The chemical supply unit  6  provides a mixed solution to the cleaning chamber  2  through the supply line  7 . The mixed solution includes a first chemical and a second chemical. The first chemical may be one of sulfuric acid, ammonia, or nitric acid. The second chemical may be hydrogen peroxide. Hereinafter, the case that the mixed solution includes sulfuric acid as the first chemical and hydrogen peroxide as the second chemical will be described as an example. 
         [0023]    The cleaning chamber  2  cleans a substrate by using the mixed solution supplied from the chemical supply unit  6 . The mixed solution used in cleaning of the substrate is recycled to be supplied to the recycling unit  3 . A portion of hydrogen peroxide included in the mixed solution becomes water in the process of being supplied to the cleaning chamber  2  and in the process of being recovered after being used in cleaning of the substrate. Therefore, sulfuric acid, hydrogen peroxide, or water may be included in the mixed solution supplied to the recycling unit  3 . 
         [0024]    The recycling unit  3  separates sulfuric acid from the recovered mixed solution. The recycling unit  3  separates sulfuric acid from the mixed solution so as to have a predetermined purity level and then provides the sulfuric acid to the chemical supply unit  6 . 
         [0025]    The chemical supply unit  6  provides the sulfuric acid supplied from the recycling unit  3  to the cleaning chamber  2  through the supply line  7 . 
         [0026]      FIG. 2  is a schematic diagram illustrating a substrate treating apparatus according to another embodiment of the present invention. 
         [0027]    Referring to  FIG. 2 , a recycling unit  3  may directly supply sulfuric acid to a cleaning chamber  2 . Therefore, sulfuric acid may be supplied from a chemical supply unit  6  to the cleaning chamber  2 , or may be supplied from the recycling unit  3  to the cleaning chamber  2 . 
         [0028]      FIG. 3  illustrates a configuration of a recycling unit. 
         [0029]    Referring to  FIG. 3 , the recycling unit  3  includes a separation unit  30 , a decompression unit  40 , and a preheating unit  50 . 
         [0030]    The separation unit  30  is connected to each one side of a recovery line  700 , a decompression line  710 , and a first discharge line  720 . The other side of the recovery line  700  is connected to the cleaning chamber  2 . Therefore, the mixed solution used in cleaning of the substrate in the cleaning chamber  2  is introduced into the separation unit  30  through the recovery line  700 . The separation unit  30  heats the mixed solution when a predetermined amount of the mixed solution is introduced into the inside thereof. When the heating of the mixed solution is continued, hydrogen peroxide and water included in the mixed solution evaporate. Also, a portion of sulfuric acid included in the mixed solution evaporates into fumes. 
         [0031]    The decompression unit  40  is installed in the decompression line  710 . The decompression unit  40  provides suction pressure to the separation unit  30  through the decompression line  710 . Therefore, gas and evaporated mixed solution in the separation unit  30  are exhausted through the decompression line  710  and pressure in the separation unit  30  decreases. When the pressure in the separation unit  30  decreases, a boiling point of the mixed solution decreases. For example, the decompression unit  40  provides pressure to allow the pressure in the separation unit  30  to be maintained within a range of 0.005 bars to 0.025 bars, and the separation unit  30  heats the mixed solution to a temperature within a range of 150° C. to 170° C. 
         [0032]    A condenser  43  to be described later is installed between the separation unit  30  and the decompression unit  40  in the decompression line  710 . 
         [0033]    A discharge value  721  and a discharge pump  722  are installed in the first discharge line  720 . The discharge value  721  blocks the circulation of the mixed solution to the first discharge line  720  during the heating of the mixed solution. Also, the mixed solution is not further introduced into the separation unit  30  while sulfuric acid is separated from the predetermined amount of the mixed solution in the separation unit  30 . Hydrogen peroxide and water mainly evaporate during the heating of the mixed solution. Therefore, purity of sulfuric acid included in the mixed solution increases when the heating of the mixed solution and the discharge of the evaporated mixed solution are continued. When the purity of sulfuric acid remaining in the separation unit  30  becomes a predetermined level, the discharge value  721  opens and the discharge pump  722  operates to discharge the sulfuric acid into the first discharge line  720 . 
         [0034]    The preheating unit  50  is installed in the recovery line  700 . The preheating unit  50  includes a housing  501  and a heater  502 . The housing  501  provides a space storing the predetermined amount of the mixed solution while constituting the exterior of the preheating unit  50 . The heater  502  heats the mixed solution stored in the housing  501 . 
         [0035]    While the sulfuric acid included in the mixed solution is separated in the separation unit  30 , the mixed solution further supplied through the recovery line  700  is stored in the housing  501  and simultaneously, heated by the heater  502 . When the sulfuric acid separated from the separation unit  30  is discharged through the first discharge line  720 , the mixed solution stored in the housing  501  or the mixed solution supplied from the cleaning chamber  2  is supplied to the separation unit  30 . Therefore, when the preheating unit  50  is installed, a temperature of the mixed solution supplied to the separation unit  30  increases and thus, time required for the mixed solution to reach an evaporation temperature may be reduced. 
         [0036]    A circulation line  730  is branched from the recovery line  700  connecting the preheating unit  50  and the separation unit  30 , and the other end of the circulation line  730  is connected to the preheating unit  50 . A first three-way valve  731  is installed where the circulation line  730  is branched from the recovery line  700 . 
         [0037]    The first three-way valve  731  is controlled to selectively open and close an inlet flow channel to the separation unit  30  or a flow channel connected to the circulation line  730 . Therefore, the mixed solution discharged from the preheating unit  50  flows into the separation unit  30  or flows again into the preheating unit  50  through the circulation line  730 . While the sulfuric acid included in the mixed solution is separated in the separation unit  30 , the three-way valve  731  is controlled to block the recovery line  700  introduced into the separation unit  30  and open the circulation line  730 , and thus, the mixed solution may circulate in the housing  501 . Therefore, a heat exchange area between the heater  502  and the mixed solution in the preheating unit  50  increases and thus, time required for heating the mixed solution is reduced. For example, the preheating unit  50  heats the mixed solution to a temperature within a range of 100° C. to 160° C. 
         [0038]    A pump  703  is installed in the recovery line  700  at a side of the preheating unit  50  having the mixed solution discharged therefrom. The pump  703  makes the circulation of the mixed solution introduced into the separation unit  30  or the circulation line  730  smoothly. 
         [0039]    The line heater  502  is installed in the recovery line  700  connecting the preheating unit  50  and the separation unit  30 . The line heater  502  is installed so as to be in contact with an outer surface of the recovery line  700  and thus, heats the mixed solution circulating in the recovery line  700 . Therefore, the line heater  502  prevents a temperature of the mixed solution discharged from the preheating unit  50  from decreasing during the circulation. Also, since a heat exchange area between the circulating mixed solution and the line heater  502  may become relatively large, a heat exchange efficiency may be improved. Further, the line heater  502  is also installed in the circulation line  730 . 
         [0040]    A second three-way valve  741  and a filter  705  are installed between the cleaning chamber  2  and the preheating unit  50  in the recovery line  700 . A waste line  740  is branched from the recovery line  700  where the second three-way valve  741  is installed. The second three-way valve  741  selectively open and close the recovery line  700  connected to the waste line  740  or the preheating unit  50 . The mixed solution introduced into the waste line  740  is discarded. Therefore, a user may recycle or discard the mixed solution by controlling the second three-way valve  741 . For example, the user may choose to discard a mixed solution used by mixing sulfuric acid and hydrogen peroxide at a ratio ranging from 1:1 to 1:4 and to recycle a mixed solution used by mixing sulfuric acid and hydrogen peroxide at a ratio ranging from 1:5 to 1:7. The filter  705  filters out foreign objects from the mixed solution introduced into the preheating unit  50 . 
         [0041]    The condenser  43  may be omitted in the present embodiment. 
         [0042]    Also, the circulation line  730  may be omitted in the present embodiment. 
         [0043]    Further, the preheating unit  50  may be omitted in the present embodiment. 
         [0044]      FIG. 4  illustrates a configuration of the separation unit  30 . 
         [0045]    Referring to  FIG. 4 , the separation unit  30  includes a housing  301 , a separation heater  302 , and a filtering member  303 . 
         [0046]    The housing  301  provides a space storing a predetermined amount of the mixed solution. The filtering member  303  is installed in the housing  301 . The filtering member  303  is provided as a porous material. When the filtering member  303  is provided, an inside of the housing is divided into an upper space and a lower space. The recovery line  700  and the first discharge line  720  are connected to the lower space and the decompression line  710  is connected to the upper space, respectively. Also, the first discharge line  720  is connected to the down side of the recovery line  700 . 
         [0047]    The separation heater  302  is installed to be able to transfer heat to the housing  301 . The separation heater  302  is installed at the inside, an inner wall, or an outer wall of the housing  301 . When the separation heater  302  is operated, the mixed solution introduced into the housing  301  is heated to evaporate. The evaporated mixed solution passes through the filtering member  303  and then moves to the decompression line  710 . Sulfuric acid is filtered from the evaporated mixed solution during the process of passing through the filtering member  303 . That is, the evaporated mixed solution collides with the filtering member  303  while passing through the filtering member  303 . A portion of the evaporated mixed solution adheres to the filtering member  303  due to viscosity during the process of colliding with the filtering member  303 . When the evaporation continues, the mixed solution adhered to the filtering member  303  is agglomerated and then drops downward due to gravity. 
         [0048]    Sulfuric acid particles included in the evaporated mixed solution have a size larger than that of hydrogen peroxide or water and have a viscosity higher than that of hydrogen peroxide or water. Accordingly, when the evaporated mixed solution collides with the filtering member  303 , an amount of sulfuric acid adhered to the filtering member  303  is greater than that of hydrogen peroxide or water adhered to the filtering member  303 . Therefore, an amount of sulfuric acid included in the mixed solution dropping from the filtering member  303  is greater than that of hydrogen peroxide or water included therein. 
         [0049]      FIG. 5  illustrates a configuration of a separation unit according to another embodiment of the present invention. 
         [0050]    Referring to  FIG. 5 , a decompression line  710  is connected to an upper space across a lower space. That is, the decompression line  710  is formed by extending from the lower space to the upper space in a housing  301  and is connected to the upper space through a hole  304  formed in a filtering member  303 . Therefore, a position at which the decompression line  710  is connected to the outside of the housing  301  is not limited to a position where the upper space is formed. Thus, the position of the decompression line  710  connected to the separation unit  30  may be changed. 
         [0051]      FIG. 6  illustrates a configuration of a condenser. 
         [0052]    Referring to  FIG. 6 , the condenser  43  includes a housing  430 , a first partition member  431 , a second partition member  432 , and connecting pipes  436 . 
         [0053]    The first partition member  431  and the second partition member  432  are installed in the housing  430  constituting the exterior of the condenser  43  to form an inlet space  433 , a cooling space  435 , and an outlet space  434 . The decompression line  710  through which the mixed solution flows in is connected to the inlet space  433 . The decompression line  710  through which the mixed solution flows out and the second discharge line  750  are connected to the outlet space  434 . The second discharge line  750  is connected to the downside of the decompression line  710  through which the mixed solution flows out. The connecting pipes  436  are installed across the cooling space  435  to connect the inlet space  433  and the outlet space  434 . Also, a coolant inlet pipe  437  and a coolant outlet pipe  438  are connected to the cooling space  435 . 
         [0054]    The evaporated mixed solution introduced into the inlet space  433  circulates to the outlet space  434  through the connecting pipes  436 . Also, the coolant introduced from the coolant inlet pipe  437  circulates the cooling space  435  and then discharged to the coolant outlet pipe  438 . The evaporated mixed solution circulating the connecting pipes  436  condenses during the process of heat exchange with the low-temperature coolant circulating the cooling space  435  and thus, a portion thereof becomes a liquid phase. The liquid-phase mixed solution circulates from the outlet space  434  to the second discharge line  750  and a gas-phase mixed solution circulates to the decompression line  710 . The mixed solution circulated to the second discharge line  750  and the decompression line  710  is discarded. 
         [0055]    Since a boiling point of the sulfuric acid included in the evaporated mixed solution is higher than those of the hydrogen peroxide and water included in the evaporated mixed solution, the sulfuric acid is easily liquefied than the hydrogen peroxide and water included in the mixed solution. Therefore, an amount of the sulfuric acid included in the mixed solution circulating from the outlet space  434  to the second discharge line  750  is larger than that included in the mixed solution circulating from the outlet space  434  to the decompression line  710 . Since the amount of the sulfuric acid introduced into the decompression unit  40  decreases, corrosion of the decompression unit  40  due to sulfuric acid is prevented. 
         [0056]    Also, an amount of the evaporated mixed solution introduced into the decompression unit  40  decreases to reduce a load applied to the decompression unit  40  and thus, energy consumed in the decompression unit  40  decreases. 
         [0057]      FIG. 7  illustrates a configuration of a preheating unit according to another embodiment of the present invention. 
         [0058]    Referring to  FIG. 7 , two preheating units  50  are provided in parallel. A recovery line  700  is branched in parallel into a first branch line  706  and a second branch line  707 . A first preheating unit  51  and a second preheating unit  52  are installed in the first branch line  706  and the second branch line  707 , respectively. Also, a third three-way valve  708  is installed where the recovery line  700  is branched. 
         [0059]    The third three-way valve  708  is controlled to allow the mixed solution introduced from the recovery line  700  to selectively flow into the first branch line  706  and the second branch line  707 . Thus, the mixed solution introduced through the recovery line  700  flows into the first preheating unit  51  or the second preheating unit  52 . Therefore, each of the first preheating unit  51  and the second preheating unit  52  may heat a predetermined amount of the mixed solution at a predetermined temperature. 
         [0060]    According to the present invention, chemicals used in cleaning of a substrate may be recycled. 
         [0061]    Also, according to the present invention, time required for recycling the chemicals used in cleaning of a substrate may be reduced. 
         [0062]    Further, according to the present invention, costs required for recycling the chemicals used in cleaning of a substrate may be reduced. 
         [0063]    The above detailed descriptions exemplify the present invention. Although the exemplary embodiments of the present invention have been described, the present invention may also be used in various other combinations, modifications, and environments. In other words, various modifications and variations can be made in the present invention without departing from the scope of the inventive concept disclosed in the present specification, the scope equivalent to the disclosure and/or the scope of technique or knowledge in the art. The exemplary embodiments have been provided to describe the best state for implementing the technical idea of the present invention and various modifications required for specific application areas and usages of the present invention can be made. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.