Patent Publication Number: US-2023158533-A1

Title: Chemical liquid supply unit, substrate processing apparatus having the same, and chemical liquid supply method

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2021-0163663, filed Nov. 24, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates generally to a chemical liquid supply unit, a substrate processing apparatus having the same, and a chemical liquid supply method. More particularly, the present disclosure relates to a technique for supplying chemical liquids of different flow rates, in which a chemical liquid is supplied at the same flow rate to each of a plurality of chemical liquid lines and the flow rate of the chemical liquid is adjusted through a flow control valve disposed on at least one chemical liquid line selected among the plurality of chemical liquid lines, so that the plurality of chemical liquid lines can supply chemical liquids at different flow rates. 
     Description of the Related Art 
     In a semiconductor manufacturing process, a process of processing a substrate using a plurality of chemical liquids is performed. 
     Depending on the type of substrate processing, a process of processing the substrate by supplying a single chemical liquid may be performed, or a process of processing the substrate by supplying a mixed chemical liquid obtained by mixing different chemical liquids in a predetermined mixing ratio may be performed. In processing the substrate by supplying these various chemical liquids, a certain process may require a high flow rate chemical liquid, and another certain process may require a low flow rate chemical liquid. 
       FIG.  1    is a view illustrating an example of a chemical liquid supply unit according to the related art. 
     As an example, in order to make a mixed chemical liquid in which three chemical liquids A, B, and C are mixed in different mixing ratios, flow controllers  30  and  40  for providing each of the chemical liquids B, and C at an adjusted flow rate are disposed, and mixing tanks  31  and  41  for mixing and supplying the chemical liquids A, B, and C are disposed. 
     There is a need to supply chemical liquids of different flow rates through a nozzle  15  of a substrate processing apparatus  10  depending on the type of substrate processing. To meet this, for example, in order to supply a high flow rate chemical liquid, the flow controller  30  for providing each of chemical liquids A, B, and C at an adjusted flow rate corresponding to the high flow rate chemical liquid and the mixing tank  31  for mixing the chemical liquids A, B, and C are disposed, and a valve  35  is disposed to supply the high flow rate chemical liquid to the nozzle  15  of the substrate processing apparatus  10 . 
     On the other hand, in order to supply a low flow rate chemical liquid, the flow controller  40  for providing each of the chemical liquids A, B, and C at an adjusted flow rate corresponding to the low flow rate chemical liquid and the mixing tank  41  for mixing the chemical liquids A, B, and C are disposed separately from the configuration for supplying the high flow rate chemical liquid, and a valve  45  is disposed to supply the low flow rate chemical liquid to the nozzle  15  of the substrate processing apparatus  1 . 
     In order to supply the chemical liquids of different flow rates as described above, the chemical liquid supply unit has to be individually disposed for each required flow rate. 
     In particular, when it is necessary to supply chemical liquids having a plurality of different flow rates, each chemical liquid supply unit is individually disposed to correspond to the number of different flow rates to be supplied. This causes an exponential increase in the number of parts, including the flow controller for controlling the flow rate of each chemical liquid, a chemical liquid supply line for each flow rate, a supply control valve, and the like. 
     The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art. 
     SUMMARY OF THE PRESENT DISCLOSURE 
     Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and an objective of the present disclosure is to provide a method of supplying chemical liquids of different flow rates through one chemical liquid supply unit according to a substrate processing process situation. 
     In particular, when it is necessary to supply chemical liquids having a plurality of different flow rates according to different substrate processing process situations, each chemical liquid supply unit is individually disposed to correspond to the number of different flow rates to be supplied. This causes an exponential increase in the number of parts, including a flow controller for controlling the flow rate of each chemical liquid, a chemical liquid supply line for each flow rate, a supply control valve, and the like. Accordingly, another objective of the present disclosure is to solve this problem. 
     The objectives of the present disclosure are not limited to those mentioned above, and other objectives not mentioned and advantages of the present disclosure will be clearly understood from the following description. 
     According to one aspect of the present disclosure, there is provided a chemical liquid supply unit including: a chemical liquid supply means configured to supply a chemical liquid; a first flow rate chemical liquid supply means configured to receive the chemical liquid from the chemical liquid supply means and supply a chemical liquid of a first flow rate to a nozzle unit of a substrate processing apparatus; a second flow rate chemical liquid supply means configured to receive the chemical liquid at the same flow rate from the chemical liquid supply means and adjust the flow rate of the chemical liquid to supply a chemical liquid of a second flow rate to the nozzle unit of the substrate processing apparatus; and a controller configured to selectively control chemical liquid supply of the first flow rate chemical liquid supply means and the second flow rate chemical liquid supply means, and control flow rate adjustment so that the chemical liquid of the second flow rate is supplied at a different flow rate from the chemical liquid of the first flow rate. 
     According to an aspect of the present disclosure, there is provided a substrate processing apparatus including: the chemical liquid supply unit; a nozzle unit configured to receive chemical liquids of different flow rates from the chemical liquid supply unit and discharge the chemical liquids to a substrate in response to a substrate processing process; and a substrate support unit on which the substrate to be processed is seated. 
     According to an aspect of the present disclosure, there is provided a method of supplying a chemical liquid, the method including: a same flow rate chemical liquid supply step of supplying a chemical liquid of a first flow rate to each of a first chemical liquid line and a second chemical liquid line branched from a chemical liquid supply line; a required flow rate determination step of determining a required chemical liquid flow rate; and a discharged chemical liquid supply step of selectively supplying the chemical liquid of the first flow rate of the first chemical liquid line or a chemical liquid of a second flow rate of which a flow rate is adjusted through the second chemical liquid line to a nozzle unit of a substrate processing apparatus according to the required chemical liquid flow rate. 
     According to an aspect of the present disclosure, there is provided a chemical liquid supply unit including: a chemical liquid supply means configured to supply a chemical liquid; a chemical liquid supply line configured to receive the chemical liquid from the chemical liquid supply means and provide the chemical liquid through a plurality of branched lines; a first chemical liquid line connected to one of the branch lines of the chemical liquid supply line and configured to supply a chemical liquid of a first flow rate to a nozzle unit of the substrate processing apparatus; a first chemical liquid line valve disposed on the first chemical liquid line and configured to selectively supply the chemical liquid of the first flow rate of the first chemical liquid line according to opening and closing operations; a second chemical liquid line connected to another one of the branch lines of the chemical liquid supply line and configured to supply a chemical liquid of a second flow rate to the nozzle unit of the substrate processing apparatus; a flow control valve disposed on the second chemical liquid line and configured to adjust the first flow rate of the chemical liquid supplied to the second chemical liquid line to a second flow rate relatively smaller than the first flow rate; a second chemical liquid line valve disposed on the second chemical liquid line and configured to selectively supply the chemical liquid of the second flow rate of the second chemical liquid line according to opening and closing operations; a recovery line configured to recovery an excess chemical liquid except for the chemical liquid of the second flow rate from the chemical liquid of the first flow rate supplied to the second chemical liquid line according to flow rate adjustment of the flow control valve; and a controller configured to control the flow control valve to adjust a flow rate of the second chemical liquid line to the second flow rate relatively smaller than the first flow rate, and control the first chemical liquid line valve and the second chemical liquid line valve to supply chemical liquids of different flow rates to the nozzle unit of the substrate processing apparatus. 
     According to the present disclosure, it is possible to supply chemical liquids of different flow rates through one chemical liquid supply unit according to a substrate processing process situation. 
     In particular, a chemical liquid is supplied at the same flow rate to each of the plurality of chemical liquid lines and the flow rate of the chemical liquid is adjusted through the flow control valve disposed on at least one chemical liquid line selected among the plurality of chemical liquid lines, so that the plurality of chemical liquid lines can supply chemical liquids at different flow rates. 
     The effects of the present disclosure are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those of ordinary skill in the art from the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a view illustrating an example of a chemical liquid supply unit according to the related art; 
         FIG.  2    is a view illustrating an example of a substrate processing apparatus to which the present disclosure is applied; 
         FIG.  3    is a block diagram illustrating the configuration of an embodiment of a chemical liquid supply unit according to the present disclosure; 
         FIG.  4    is a view illustrating a first embodiment of a chemical liquid supply unit according to the present disclosure; 
         FIG.  5    is a view illustrating a second embodiment of a chemical liquid supply unit according to the present disclosure; 
         FIGS.  6  and  7    are views illustrating a third embodiment of a chemical liquid supply unit according to the present disclosure; 
         FIG.  8    is a flowchart illustrating an embodiment of a chemical liquid supply method according to the present disclosure; 
         FIG.  9    is a flowchart illustrating an embodiment in which a chemical liquid is supplied through a chemical liquid supply means in the chemical liquid supply method according to the present disclosure; 
         FIG.  10    is a flowchart illustrating an embodiment in which a chemical liquid is supplied at a first flow rate in the chemical liquid supply method according to the present disclosure; 
         FIG.  11    is a view illustrating the embodiment in which the chemical liquid is supplied at the first flow rate in the substrate processing apparatus according to the present disclosure; 
         FIG.  12    is a flowchart illustrating an embodiment in which a chemical liquid is supplied at a second flow rate in the chemical liquid supply method according to the present disclosure; 
         FIG.  13    is a flowchart illustrating a first embodiment of processing an excess chemical liquid in the chemical liquid supply method according to the present disclosure; 
         FIG.  14    is a view illustrating the first embodiment of processing the excess chemical liquid in the substrate processing apparatus according to the present disclosure; 
         FIG.  15    is a flowchart illustrating a second embodiment of processing an excess chemical liquid in the chemical liquid supply method according to the present disclosure; 
         FIG.  16    is a view illustrating the second embodiment of processing the excess chemical liquid in the substrate processing apparatus according to the present disclosure; 
         FIG.  17    is a flowchart illustrating a third embodiment of processing an excess chemical liquid in the chemical liquid supply method according to the present disclosure; and 
         FIGS.  18  to  20    are views illustrating the third embodiment of processing the excess chemical liquid in the substrate processing apparatus according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, but the present disclosure is not limited by these embodiments. 
     The present disclosure, operational advantages of the present disclosure, and objectives achieved by executing the present disclosure will be, hereinafter, described by exemplifying embodiments of the present disclosure and referring to the exemplified embodiments. 
     First, terms used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, it will be understood that the terms “comprise”, “include”, and/or “have” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Meanwhile, in the following description, a detailed description of related known configurations or functions may be omitted to avoid obscuring the subject matter of the present disclosure. 
     The present disclosure provides a technique for supplying chemical liquids of different flow rates, in which a chemical liquid is supplied at the same flow rate to each of a plurality of chemical liquid lines and the flow rate of the chemical liquid is adjusted through a flow control valve disposed on at least one chemical liquid line selected among the plurality of chemical liquid lines, so that the plurality of chemical liquid lines can supply chemical liquids at different flow rates. 
       FIG.  2    is a view illustrating an example of a substrate processing apparatus to which the present disclosure is applied. 
     The substrate processing apparatus  100  may include a processing container  120 , a substrate support unit  140 , a lifting unit  160 , a nozzle unit  170 , and the like. 
     The processing container  120  may have a processing space therein, and may have a cylindrical shape with an open top. The processing container  120  may include a first recovery tub  122 , a second recovery tub  124 , and a third recovery tub  126 . Each of the recovery tubs  122 ,  124 , and  126  may recovers each type of processing liquid used in a process. The first recovery tub  122  may be provided in an annular ring shape surrounding the substrate support unit  140 , the second recovery tub  124  may be provided in an annular ring shape surrounding the first recovery tub  122 , and the third recovery tub  126  may be provided in an annular ring shape surrounding the second recovery tub  124 . An inner space of the first recovery tub  122  may function as a first inlet  122   a  through which a liquid flows. A space between the second recovery tub  124  and the first recovery tub  122  may function as a second inlet  124   a  through which a liquid flows into the second recovery tub  124 . A space between the second recovery tub  124  and the third recovery tub  126  may function as a third inlet  126   a  through which a liquid flows into the third recovery tub  126 . According to an example, each of the inlets  122   a ,  124   a , and  126   a  may be located at different heights. Recovery pipes  122   b ,  124   b , and  126   b  may be connected to the bottom of the recovery tubs  122 ,  124 , and  126 , respectively. 
     The substrate support unit  140  may support a substrate W. The substrate support unit  140  may rotate the substrate W during the process. The substrate support unit  140  may include a body  142 , a support pin  144 , a chuck pin  146 , and a support shaft  148 . The body  142  may have an upper surface and a lower surface that are provided in a circular shape. The upper and lower surfaces of the body  142  may be located so that the central axes coincide with each other. The support shaft  148  rotatable by a driving unit  149  may be fixedly coupled to the lower surface of the body  142 . 
     A plurality of support pins  144  may be provided. The support pins  144  may be arranged to be spaced apart from each other at a predetermined interval on an outer peripheral portion of the upper surface of the body  142  and may be formed to protrude upward from the body  142 . The support pins  144  may be arranged to form a substantially annular ring shape by combination with each other. The support pins  144  may support an outer peripheral portion of a rear surface of the substrate W so that the substrate W is spaced apart a predetermined distance from the upper surface of the body  142 . 
     A plurality of chuck pins  146  may be provided. The chuck pins  146  may be arranged farther from the center of the body  142  than the support pins  144 . The chuck pins  146  may be provided to protrude upward from the body  142 . The chuck pins  146  may support lateral side portions of the substrate W so as to prevent the substrate W from being laterally deviated from the original position thereof when the substrate W is rotated. The chuck pins  146  may be provided to be movable linearly between a standby position and a supporting position along a radial direction of the body  142 . The standby position may be a position farther from the center of the body  142  than the supporting position. When the substrate W is loaded on or unloaded from the substrate support unit  140 , the chuck pins  146  may be positioned at the standby position, and when the process is performed on the substrate W, the chuck pins  146  may be positioned at the supporting position. In the supporting position, the chuck pins  146  may be in contact with the lateral side portions of the substrate W. 
     The lifting unit  160  may adjust a relative height between the processing container  120  and the substrate support unit  140 . The lifting unit  160  may linearly move the processing container  120  upward and downward. As the processing container  120  may be moved upward and downward, the relative height of the processing container  120  with respect to the substrate support unit  140  may be changed. The lifting unit  160  may include a bracket  162 , a moving shaft  164 , an actuator  166 , and the like. The bracket  162  may be fixedly installed on an outer wall of the processing container  120 , and the moving shaft  164  moved upward and downward by the actuator  166  may be fixedly coupled to the bracket  162 . The processing container  120  may be moved downward so that the substrate support unit  140  protrudes above the processing container  120  when the substrate W is loaded on or unloaded from the substrate support unit  140 . Furthermore, when the process is performed, the height of the processing container  120  may be adjusted so that a processing liquid is introduced into a predetermined one of the recovery tubs  122 ,  124 , and  126  according to the type of the processing liquid supplied to the substrate W. Optionally, the height of the processing container  120  may be fixed, and the body  142  of the substrate support unit  140  may be moved upward and downward. 
     The nozzle unit  170  may supply various chemical liquids on the substrate W. The nozzle unit  170  may include a first nozzle member  170   a  (i.e., a first nozzle), a second nozzle member  170   b  (i.e., a second nozzle), a rinse nozzle member  170   c  (i.e., a rinse nozzle), and the like. The number of the nozzle members may be changed as needed. 
     The first nozzle member  170   a  may supply a first liquid, the second nozzle member  170   b  may supply a second liquid, and the rinse nozzle member  170   c  may supply a rinse liquid. According to an example, the first liquid may be a strong acid chemical including sulfuric acid (H 2 SO 4 ) The second liquid may be an alkaline liquid including an organic solvent. The organic solvent may be isopropyl alcohol (IPA). The rinse liquid may be pure water (H 2 O). 
     The first nozzle member  170   a  may include a first nozzle moving member  171  and a first nozzle  174   a . The first nozzle moving member  171  may move the first nozzle  174   a  to a process position and a standby position. Here, the process position may be a position where the first nozzle  174   a  faces the substrate W supported by the substrate support unit  140 , and the standby position may be a position where the first nozzle  174   a  is deviated from the process position. According to an example, the standby position may be a position where the first nozzle  174   a  is standby in a first standby port. The first nozzle moving member  171  may include a rotation shaft  176 , an actuator  178 , and a support arm  172 . The rotation shaft  176  may be located at a side of the processing container  120 . The rotation shaft  176  may be rotated by the actuator  178 . The rotation shaft  176  may be rotated about the central axis thereof by a driving force provided from the actuator  178 . The support arm  172  may connect the first nozzle  174   a  and the rotation shaft  176  to each other. As the rotation shaft  176  may be rotated, the support arm  172  and the first nozzle  174   a  may be rotated about the central axis of the rotation shaft  176 . 
     The support arm  172  may be provided in a rod shape oriented in a longitudinal direction orthogonal to the rotation shaft  176 . A first end of the support arm  172  may be fixedly coupled to an upper end of the rotation shaft  176 . The support arm  172  may be rotated about the first end thereof coupled to the rotation shaft  176 . The first nozzle  174   a  may be coupled to a second end of the support arm  172 . According to an example, a moving path of the first nozzle  174   a  may be provided to pass through the center of the substrate W when viewed from the top. Therefore, the first nozzle  174   a  may be moved to the process position and the standby position as the rotation shaft  176  and the support arm  172  may be rotated. 
     The second nozzle member  170   b  may include a second nozzle moving member and a second nozzle  174   b . The second nozzle moving member may move the second nozzle  174   b  to a process position and a standby position. Here, the process position may be a position where the second nozzle  174   b  faces the substrate W supported by the substrate support unit  140 , and the standby position may be a position where the second nozzle  174   b  is deviated from the process position. The second nozzle moving member may have the same configuration as the first nozzle moving member  171 , so a detailed description thereof will be omitted. 
     The rinse nozzle member  170   c  may include a rinse nozzle moving member and a rinse nozzle  174   c . The rinse nozzle member  170   c  may move the rinse nozzle  174   c  to a process position and a standby position. Here, the process position may be a position where the rinse nozzle  174   c  faces the substrate W supported by the substrate support unit  140 , and the standby position may be a position where the rinse nozzle  174   c  is deviated from the process position. The rinse nozzle moving member may have the same configuration as the first nozzle moving member  171 , so a detailed description thereof will be omitted. 
     The controller  150  may control the lifting unit  160  and the nozzle unit  170 . The controller  150  may control each unit so that a first liquid supply step of supplying the first liquid on the substrate W and a second liquid supply step of supplying the second liquid on the substrate W are sequentially performed. The controller  150  may control the lifting unit  160  so that the substrate W corresponds to the first inlet  122   a  in the first liquid supply step and the substrate W corresponds to the second inlet  124   a  in the second liquid supply step. 
     According to an example, the controller  150  may lock the second nozzle member  170   b  so that the second liquid is not discharged while the first liquid is discharged, and may lock the first nozzle member  170   a  so that the first liquid is not discharged while the second liquid is discharged. Therefore, it is possible to prevent the first liquid and the second liquid from mixing. 
     Furthermore, the controller  150  may lock the second nozzle member  170   b  so that the second liquid is not discharged when the first inlet  122   a  of the processing container  120  is positioned to correspond to the substrate W, and may lock the first nozzle member  170   a  so that the first liquid is not discharged when the second inlet  124   a  of the processing container  120  is positioned to correspond to the substrate W. Therefore, it is possible to prevent the first liquid from being recovered to the second recovery tub  124  or the second liquid from being recovered to the first recovery tub  122 . 
     Furthermore, the controller  150  may release the locking of one nozzle member positioned at the standby position among the first nozzle member  170   a  and the second nozzle member  170   b . Therefore, it is possible to prevent a nozzle member for performing preliminary discharge from being locked. 
     The nozzle unit  170  may discharge a plurality of different chemical liquids and chemical liquids of different flow rates to the substrate W through the nozzle members  170   a ,  170   b , and  170   c . In the present disclosure, a chemical liquid supply unit  200  for supplying chemical liquids of different flow rates to the nozzle unit  170  is provided, and the substrate processing apparatus  100  to which the chemical liquid supply unit  200  according to the present disclosure is applied is also provided. 
     The chemical liquid supply unit  200  according to the present disclosure will be described through embodiments. 
       FIG.  3    is a block diagram illustrating the configuration of an embodiment of a chemical liquid supply unit  200  according to the present disclosure. 
     The chemical liquid supply unit  200  may include a chemical liquid supply means  210  (i.e., a chemical supply source), a first flow rate chemical liquid supply means  230  (i.e., a first flow rate chemical liquid supply line), a second flow rate chemical liquid supply means  250  (i.e., a second flow rate chemical liquid supply line), an excess chemical liquid processing means  270  (i.e., an excess chemical line drain line), a controller  290 , and the like. 
     The chemical liquid supply means  210  may include at least one chemical liquid sources, and may supply a chemical liquid from the chemical liquid source to the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250 . 
     As an example, the chemical liquid supply means  210  may supply a chemical liquid from one chemical liquid source, and alternatively, the chemical liquid supply means  210  may mix chemical liquids supplied from a plurality of chemical liquid sources in an adjusted mixing ratio and then supply the mixture at the same constant flow rate to each of the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250 . 
     Each of the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250  may supply the chemical liquid at a different flow rate to a nozzle unit  170  of a substrate processing apparatus  100 . 
     For example, the first flow rate chemical liquid supply means  230  may supply a high flow rate chemical liquid to the nozzle unit  170  of the substrate processing apparatus  100 , and the second flow rate chemical liquid supply means  250  may supply a low flow rate chemical liquid to the nozzle unit  170  of the substrate processing apparatus  100 . 
     The first flow rate chemical liquid supply means  230  may supply the chemical liquid supplied from the chemical liquid supply means  210  to the nozzle unit  170  of the substrate processing apparatus  100 , without adjusting the flow rate of the chemical liquid. 
     The second flow rate chemical liquid supply means  250  may adjust the flow rate of the chemical liquid supplied from the chemical liquid supply means  210  to a flow rate required in a corresponding substrate processing process, and supply the chemical liquid at the adjusted flow rate to the nozzle unit  170  of the substrate processing apparatus  100 . 
     To this end, the second flow rate chemical liquid supply means  250  may include a flow control valve to adjust the flow rate of the chemical liquid supplied from the chemical liquid supply means  210 . 
     In other words, in the chemical liquid supply unit  200  according to the present disclosure, while the chemical liquids of the same flow rate are supplied from one chemical liquid supply means  210 , the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250  may adjust the flow rate to different flow rates to selectively supply the chemical liquids of different flow rates to the nozzle unit  170  of the substrate processing apparatus  100 . 
     The excess chemical liquid processing means  270  may process an excess chemical liquid remaining after the flow rate of the chemical liquid is adjusted through the second flow rate chemical liquid supply means  250 . 
     As an example, the excess chemical liquid processing means  270  may discharge the excess chemical liquid remaining after the flow rate is adjusted through the second flow rate chemical liquid supply means  250  to the outside. 
     As another example, the excess chemical liquid processing means  270  may recover the excess chemical liquid remaining after the flow rate is adjusted through the second flow rate chemical liquid supply means  250  and provide the recovered chemical liquid for reuse in the chemical liquid supply means  210 . 
     The controller  290  may control the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250  to selectively supply the chemical liquids of different flow rates to the nozzle unit  170  of the substrate processing apparatus  100 . 
     As an example, the controller  290  may control the flow control valve provided at the second flow rate chemical liquid supply means  250  to adjust the flow rate of the chemical liquid to a flow rate required in the corresponding substrate processing process. Furthermore, the controller  290  may control a valve provided at each of the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250  to selectively control the flow of the chemical liquid to be supplied to the nozzle unit  170  of the substrate processing apparatus  100 . 
     Moreover, the controller  290  may control the excess chemical liquid processing means  270  to discharge the excess chemical liquid to the outside through the excess chemical liquid processing means  270  or to recover the excess chemical liquid for reuse. 
     The chemical liquid supply unit  200  according to the present disclosure will be described in more detail through specific embodiments. 
       FIG.  4    is a view illustrating a first embodiment of a chemical liquid supply unit  200  according to the present disclosure. 
     A chemical liquid supply means  210  may include a plurality of chemical liquid sources  211   a ,  211   b , and  211   c  of a plurality of chemical liquids A, B, and C to provide the chemical liquids A, B, and C, and may include a flow controller  213  for adjusting the flow rate of each of the chemical liquid sources  211   a ,  211   b , and  211   c  to adjust the ratio of each of the chemical liquids A, B, and C to be supplied. In an embodiment, the plurality of chemical sources  211   a ,  211   b , and  211   c  may include a plurality of chemical liquid supply tanks  212   a ,  212   b , and  212   c , respectively. The plurality of chemical liquid supply tanks  212   a ,  212   b , and  212   c  may store the chemical liquids A, B, and C different from each other in kind. 
     The chemical liquid supply means  210  may mix the chemical liquids B, and C in a required mixing ratio in a mixing tank  215  to form and supply a mixed chemical liquid. In this embodiment, the chemical liquid supply means  210  is described as being provided with the mixing tank  215  to mix and supply the plurality of chemical liquids, but depending on situation, the chemical liquid supply means  210  may be provided with a simple mixer to mix and supply the plurality of chemical liquids. 
     The chemical liquid supply means  210  may supply the chemical liquid to each of a first flow rate chemical liquid supply means  230  and a second flow rate chemical liquid supply means  250  through a chemical liquid supply line  217  connected to the mixing tank  215 . 
     The chemical liquid supply line  217  may have a first side connected to the mixing tank  215  and a second side branched into a plurality of branch lines, and may supply the chemical liquid to the first flow rate chemical liquid supply means  230  through one of the branch lines and supply the chemical liquid to the second flow rate chemical liquid supply means  250  through another one of the branch lines. 
     Here, the chemical liquid supply line  217  may supply chemical liquids of the same flow rate to the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250 . 
     The first flow rate chemical liquid supply means  230  may include a first chemical liquid line  231 . The first chemical liquid line  231  may be connected to one of the branch lines of the chemical liquid supply line  217  to receive the chemical liquid. 
     Furthermore, the first flow rate chemical liquid supply means  230  may include a first chemical liquid line valve  232  disposed on the first chemical liquid line  231 . Opening and closing operations of the first chemical liquid line valve  232  may be operated under control of a controller  290 , so that the chemical liquid may be selectively supplied to a nozzle unit  170  of a substrate processing apparatus  100  through the first chemical liquid line  231 . 
     As an example, the chemical liquid supply line  217  may supply a chemical liquid of a first flow rate, and the first flow rate chemical liquid supply means  230  may supply the chemical liquid of the first flow rate supplied from the chemical liquid supply line  217  to the nozzle unit  170  of the substrate processing apparatus  100 , without adjusting the first flow rate of the chemical liquid. For example, when a substrate processing process is performed using a high flow rate chemical liquid, the high flow rate chemical liquid may be supplied to the nozzle unit  170  of the substrate processing apparatus  100  through the first flow rate chemical liquid supply means  230  and discharged in a liquid state to a substrate W through the nozzle unit  170 . 
     The second flow rate chemical liquid supply means  250  may include a second chemical liquid line  251 . The second chemical liquid line  251  may be connected to another one of the branch lines of the chemical liquid supply line  217  to receive the chemical liquid. 
     The second flow rate chemical liquid supply means  250  may include a flow control valve  253  and a second chemical liquid line valve  252  disposed on the second chemical liquid line  251 . 
     The controller  290  may control the flow control valve  253  to adjust the flow rate of the chemical liquid of the second chemical liquid line  251  to a flow rate required in a corresponding substrate processing process. As the flow control valve  253 , various methods for finely adjusting the flow rate may be employed. As an example, a needle valve may be employed to adjust the flow rate of the chemical liquid flowing on the second chemical liquid line  251  to a fine level. 
     The controller  290  may control opening and closing operations of the second chemical liquid line valve  252  to selectively supply the chemical liquid at the adjusted flow rate to the nozzle unit  170  of the substrate processing apparatus  100  through the second chemical liquid line  251 . 
     As an example, the second flow rate chemical liquid supply means  250  may receive the chemical liquid of the first flow rate from the chemical liquid supply line  217  at the same flow rate as the first chemical liquid supply means  230 , and may adjust the first flow rate to a second flow rate required in the corresponding substrate processing process through the flow control valve  253  and supply a chemical liquid of the second flow rate to the nozzle unit  170  of the substrate processing apparatus  100 . For example, when a substrate processing process is performed using a low flow rate chemical liquid, the low flow rate chemical liquid may be supplied to the nozzle unit  170  of the substrate processing apparatus  100  through the second flow rate chemical liquid supply means  250  and discharged in a spray state to the substrate W through the nozzle unit  170 . 
     The chemical liquid supply line  217  of the chemical liquid supply means  210  may supply the chemical liquids of the same flow rate to the first chemical liquid line  231  and the second chemical liquid line  251 . However, since the second flow rate chemical liquid supply means  250  may supply the chemical liquid at the adjusted flow rate to the nozzle unit  170  of the substrate processing apparatus  100 , an excess chemical liquid may remain. 
     An excess chemical liquid processing means  270  may include an excess chemical liquid line  271 , an excess chemical liquid valve  272 , a drain line  273 , and the like for processing the excess chemical liquid remaining after the flow rate is adjusted through the second chemical liquid line  251 . 
     The excess chemical liquid except for the chemical liquid of which the flow rate is adjusted through the second flow rate chemical liquid supply means  250  from the chemical liquid supplied from the chemical liquid supply line  217  may be introduced into the excess chemical liquid line  271 , and the controller  290  may control opening and closing operations of the excess chemical liquid valve  272  to discharge the excess chemical liquid to the outside through the drain line  273 . 
     In other words, in the chemical liquid supply unit  200  according to the present disclosure, while the chemical liquids of the same flow rate are supplied from one chemical liquid supply means  210 , the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250  may selectively supply the chemical liquids of different flow rates to the nozzle unit  170  of the substrate processing apparatus  100 . 
     Furthermore, in the present disclosure, the excess chemical liquid processing means  270  for processing the excess chemical liquid remaining after the flow rate is adjusted through the second flow rate chemical liquid supply means  250  may be variously modified. The excess chemical liquid processing means  270  will be described in more detail through various embodiments. 
       FIG.  5    is a view illustrating a second embodiment of a chemical liquid supply unit  200  according to the present disclosure. 
     In the second embodiment of the chemical liquid supply unit  200 , a chemical liquid supply means  210 , a first flow rate chemical liquid supply means  230 , a second flow rate chemical liquid supply means  250 , and the like remain the same as or similar to those of the first embodiment of the chemical liquid supply unit  200  described above, so a detailed description thereof will be omitted in order to avoid an overlapping description. 
     An excess chemical liquid processing means  270  may include an excess chemical liquid line  271 , an excess chemical liquid valve  272 , a recovery line  274 , and the like for recovering and reusing an excess chemical liquid remaining after the flow rate of a chemical liquid is adjusted through a second chemical liquid line  251 . 
     The excess chemical liquid except for the chemical liquid of which the flow rate is adjusted through the second flow rate chemical liquid supply means  250  from the chemical liquid supplied from a chemical liquid supply line  217  may be introduced into the excess chemical liquid line  271 , and a controller  290  may control opening and closing operations of the excess chemical liquid valve  272  to recover the excess chemical liquid through the recovery line  274 . 
     The recovery line  274  may be connected to a mixing tank  215  of the chemical liquid supply unit  200 , so that the recovered chemical liquid recovered through the recovery line  274  may be supplied to the mixing tank  215  of the chemical liquid supply unit  200  to be used again. 
     Furthermore, the recovery line  274  may be connected to the chemical liquid supply line  217  of the chemical liquid supply means  210 , so that the recovered chemical liquid recovered through the recovery line  274  may be directly supplied to the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250  without passing through the mixing tank  215 . 
       FIGS.  6  and  7    are views illustrating a third embodiment of a chemical liquid supply unit  200  according to the present disclosure. 
     In the third embodiment of the chemical liquid supply unit  200 , a chemical liquid supply means  210 , a first flow rate chemical liquid supply means  230 , a second flow rate chemical liquid supply means  250 , and the like remain the same as or similar to those of the first embodiment of the chemical liquid supply unit  200  described above, so a detailed description thereof will be omitted in order to avoid an overlapping description. 
     An excess chemical liquid processing means  270  may include an excess chemical liquid line  271 , an excess chemical liquid valve  272 , a recovery line  275 , a storage tank  276 , a recovered chemical liquid supply line  278 , a recovery valve  279 , and the like for recovering and reusing an excess chemical liquid remaining after the flow rate of a chemical liquid is adjusted through a second chemical liquid line  251 . 
     The excess chemical liquid except for the chemical liquid of which the flow rate is adjusted through the second flow rate chemical liquid supply means  250  from the chemical liquid supplied from a chemical liquid supply line  217  may be introduced into the excess chemical liquid line  271 , and a controller  290  may control opening and closing operations of the excess chemical liquid valve  272  to recover the excess chemical liquid through the recovery line  275 . The recovery line  274  may be connected to the storage tank  276  to supply the recovered chemical liquid to the storage tank  276 . 
     The storage tank  276  may temporarily store the recovered chemical liquid. 
     In the embodiment of  FIG.  6   , the recovered chemical liquid stored in the storage tank  276  may be supplied to a mixing tank  215  of the chemical liquid supply unit  200  through the recovered chemical liquid supply line  278  to be used again. 
     In the embodiment of  FIG.  7   , the recovered chemical liquid stored in the storage tank  276  may be supplied to the chemical liquid supply line  217  of the chemical liquid supply unit  200  through a recovered chemical liquid supply line  278   a  to be used again. 
     The controller  290  may control the recovery valve  279  disposed on the recovered chemical liquid supply line  278  to selectively provide the recovered chemical liquid stored in the storage tank  276 . 
     The excess chemical liquid processing means  270  may further include a circulation line  277 . A heater (not illustrated), a pump (not illustrated), a filter (not illustrated), and the like may be disposed on the circulation line  277 . While the recovered chemical liquid stored in the storage tank  276  is circulated through the circulation line  277 , the recovered chemical liquid may be adjusted according to control of chemical liquid supply. A new chemical liquid for adjusting the recovered chemical liquid may be supplied to the storage tank  276  or the circulation line  277  as needed. 
     As described above, the chemical liquid supply unit  200  according to the present disclosure may selectively supply the chemical liquid at different flow rates to the nozzle unit  170  of the substrate processing apparatus  100  through the first flow rate chemical liquid supply means  230  and the second flow rate chemical liquid supply means  250  and may recover and reuse the excess chemical liquid remaining after flow rate adjustment. 
     In the present disclosure, a method of supplying a chemical liquid through the above-described chemical liquid supply unit according to the present disclosure is provided. Hereinafter, a chemical liquid supply method according to the present disclosure will be described through embodiments. Since the chemical liquid supply method according to the present disclosure may be implemented in the above-described chemical liquid supply unit according to the present disclosure, the embodiments of the chemical liquid supply unit according to the present disclosure will be referred to together. 
       FIG.  8    is a flowchart illustrating an embodiment of a chemical liquid supply method according to the present disclosure. 
     A chemical liquid supply means  210  may supply a chemical liquid to each of a first flow rate chemical liquid supply means  230  and a second flow rate chemical liquid supply means  250 . At this time, a chemical liquid of a first flow rate may be supplied to each of a first chemical liquid line  231  of the first flow rate chemical liquid supply means  230  and a second chemical liquid line  251  of the second flow rate chemical liquid supply means  250 , the first and second liquid lines  231  and  251  being branched from a chemical liquid supply line  217  (S 110 ). 
     Here, the chemical liquid supplied by the chemical liquid supply means  210  may be one chemical liquid or a mixed chemical liquid in which a plurality of different chemical liquids are mixed in a required mixing ratio. 
     A controller  290  may determine a required chemical liquid flow rate required in a corresponding substrate processing process (S 150 ), and when the first flow rate is required, the controller  290  may selectively operate the first flow rate chemical liquid supply means  230  (S 210 ). At this time, the controller  290  may stop the operation of the second flow rate chemical liquid supply means  250 . 
     The first flow rate chemical liquid supply means  230  may supply the chemical liquid of the first flow rate supplied from the chemical liquid supply means  210 , without adjusting the first flow rate of the chemical liquid, and the first flow rate chemical liquid supply means  230  may supply the chemical liquid of the first flow rate to a nozzle unit  170  of a substrate processing apparatus  100  under control of the controller  290  (S 250 ). 
     On the other hand, when a second flow rate is required as a result of the determination on the required chemical liquid flow rate required in the corresponding substrate processing process (S 150 ), the controller  290  may selectively operate the second flow rate chemical liquid supply means  250  (S 310 ). At this time, the controller  290  may stop the operation of the first flow rate chemical liquid supply means  230 . 
     The controller  290  may control the second flow rate chemical liquid supply means  250  to adjust the flow rate of the supplied chemical liquid (S 330 ), and may adjust the first flow rate of the chemical liquid supplied from the chemical liquid supply means  210  to the second flow rate (S 330 ). 
     The second flow rate chemical liquid supply means  250  may supply a chemical liquid of a second flow rate to the nozzle unit  170  of the substrate processing apparatus  100  under control of the controller  290  (S 350 ). 
     Each process of the chemical liquid supply method according to the present disclosure will be described in more detail through more specific embodiments. 
       FIG.  9    is a flowchart illustrating an embodiment in which a chemical liquid is supplied through a chemical liquid supply means  210  in the chemical liquid supply method according to the present disclosure. 
     The chemical liquid supply means  210  may supply a mixed chemical liquid in which a plurality of different chemical liquids are mixed in a required mixing ratio. 
     To this end, the chemical liquid supply means  210  may receive the chemical liquids from a plurality of chemical liquid sources  211   a ,  211   b , and  211   c , and adjust the flow rate of each of the chemical liquids through a flow controller  213  according to the required mixing ratio (S 111 ). 
     The chemical liquids of which the flow rates are adjusted may be supplied to the mixing tank  215  of the chemical liquid supply means  210  (S 113 ) and mixed in the mixing tank  215  to form the mixed chemical liquid. 
     The chemical liquid in the mixing tank  215  may be supplied to each of a first chemical liquid line  231  of the first flow rate chemical liquid supply means  230  and a second chemical liquid line  251  of the second flow rate chemical liquid supply means  250  through a chemical liquid supply line  217  of the chemical liquid supply means  210  (S 115 ). 
     At this time, the flow rates of the chemical liquids supplied from the chemical liquid supply line  217  to the first chemical liquid line  231  and the second chemical liquid line  251  may be the same. 
     Next, an example of supplying a chemical liquid of a first flow rate to a processing unit of a substrate processing apparatus  100  according to the present disclosure will be described. 
       FIG.  10    is a flowchart illustrating an embodiment in which a chemical liquid is supplied at a first flow rate in the chemical liquid supply method according to the present disclosure.  FIG.  11    is a view illustrating the embodiment in which the chemical liquid is supplied at the first flow rate in the substrate processing apparatus  100  according to the present disclosure. 
     A controller  290  may determine a required chemical liquid flow rate required in a corresponding substrate processing process, and when the first flow rate is required, may open a first chemical liquid line valve  232  disposed on a first chemical liquid line  231  and close a second chemical liquid line valve  252  disposed on a second chemical liquid line  251  (S 211 ). 
     With the opening of the first chemical liquid line valve  232 , the chemical liquid of the first flow rate may be supplied to a nozzle unit  170  of the substrate processing apparatus  100  through the first chemical liquid line  231  (S 251 ). 
     Here, since a first flow rate chemical liquid supply means  230  may supply the chemical liquid supplied from a chemical liquid supply line  217  of a chemical liquid supply means  210  without adjusting the first flow rate of the chemical liquid, the chemical liquid supplied to the nozzle unit  170  of the substrate processing apparatus  100  through the first flow rate chemical liquid supply means  230  may be a first flow rate chemical liquid having a high flow rate. Therefore, a high flow rate chemical liquid may be discharged in a liquid state through the nozzle unit  170  of the substrate processing apparatus  100  (S 255 ). 
     Next, an example of supplying a chemical liquid of a second flow rate to a processing unit of a substrate processing apparatus  100  and processing an excess chemical liquid according to the present disclosure will be described. 
       FIG.  12    is a flowchart illustrating an embodiment in which a chemical liquid is supplied at a second flow rate in the chemical liquid supply method according to the present disclosure.  FIG.  13    is a flowchart illustrating a first embodiment of processing an excess chemical liquid in the chemical liquid supply method according to the present disclosure.  FIG.  14    is a view illustrating the first embodiment of processing the excess chemical liquid in the substrate processing apparatus  100  according to the present disclosure. 
     First, a process of supplying the chemical liquid at the second flow rate will be described with reference to the embodiments of  FIGS.  12  and  14   . 
     A controller  290  may determine a required chemical liquid flow rate required in a corresponding substrate processing process, and when the second flow rate is required, may close a first chemical liquid line valve  232  (S 311 ). 
     Then, the controller  290  may control a flow control valve  253  disposed on a second chemical liquid line  251  to adjust a first flow rate of a chemical liquid flowing on the second chemical liquid line  251  to the second flow rate (S 331 ). 
     When the flow rate is adjusted to a required flow rate level through the flow control valve  253 , the controller  290  may open a second chemical liquid line valve  252  disposed on the second chemical liquid line  251  (S 335 ) to supply the chemical liquid of the second flow rate to a nozzle unit  170  of the substrate processing apparatus  100  (S 351 ). 
     Here, since the controller  290  may adjust the first flow rate of the chemical liquid supplied from a chemical liquid supply line  217  of a chemical liquid supply means  210  to the second flow rate through the flow control valve  253  of a second flow rate chemical liquid supply means  250 , the chemical liquid supplied to the nozzle unit  170  of the substrate processing apparatus  100  through the second flow rate chemical liquid supply means  250  may be a second flow rate chemical liquid having a low flow rate. Therefore, a low flow rate chemical liquid may be discharged in a spray state through the nozzle unit  170  of the substrate processing apparatus  100  (S 355 ). 
     Since the second flow rate chemical liquid supply means  250  may supply the chemical liquid of the second flow rate having a relatively small flow rate by adjusting the chemical liquid of the first flow rate supplied from the chemical liquid supply means  210 , the excess chemical liquid except for the chemical liquid of the second flow rate from the chemical liquid of the first flow rate may remain. 
     An excess chemical liquid processing means  270  may process the excess chemical liquid remaining after the chemical liquid of the second flow rate is supplied through the second flow rate chemical liquid supply means  250  (S 400 ). 
     A process of processing the excess chemical liquid remaining after supplying the chemical liquid of the second flow rate will be described with reference to the embodiments of  FIGS.  13  and  14   . 
     The excess chemical liquid remaining in the second flow rate chemical liquid supply means  250  may be introduced into an excess chemical liquid line  271  of the excess chemical liquid processing means  270 . 
     The controller  290  may selectively open an excess chemical liquid valve  272  disposed on the excess chemical liquid line  271  to discharge the excess chemical liquid to the outside through a drain line  273  (S 413 ). 
     The process of processing the excess chemical liquid may be variously modified in the present disclosure. In this regard,  FIG.  15    is a flowchart illustrating a second embodiment of processing an excess chemical liquid in the chemical liquid supply method according to the present disclosure.  FIG.  16    is a view illustrating the second embodiment of processing the excess chemical liquid in the substrate processing apparatus  100  according to the present disclosure. 
     A process of supplying a chemical liquid of a second flow rate prior to the process of processing the excess chemical liquid remains the same as or similar to that described with reference to  FIGS.  12  and  14   , so a detailed description thereof will be omitted. 
     The excess chemical liquid remaining in a second flow rate chemical liquid supply means  250  may be introduced into an excess chemical liquid line  271  of an excess chemical liquid processing means  270 . 
     The excess chemical liquid processing means  270  may include a recovery line  274 , and a controller  290  may selectively open an excess chemical liquid valve  272  disposed on the excess chemical liquid line  271  (S 421 ) to recover the excess chemical liquid of the excess chemical liquid line  271  to the recovery line  274  (S 423 ). 
     The recovery line  274  of the excess chemical liquid processing means  270  may be connected to a chemical liquid supply line  217  of a chemical liquid supply means  210 , so that the recovered chemical liquid of the recovery line  274  may be supplied to the chemical liquid supply line  271  (S 425 ). As the recovery line  274  may be connected to the chemical liquid supply line  217 , the recovered chemical liquid of the recovery line  274  may be directly supplied to a first flow rate chemical liquid supply means  230  or the second flow rate chemical liquid supply means  250  through the chemical liquid supply line  217 . 
     Furthermore, as illustrated in  FIG.  16   , the recovery line  274  of the excess chemical liquid processing means  270  may be connected to a mixing tank  215  of the chemical liquid supply means  210 . The recovered chemical liquid recovered to the recovery line  274  may be supplied to the mixing tank  215  of the chemical liquid supply means  210  to be used again through the mixing tank  215 . 
     Another embodiment of a process of processing an excess chemical liquid will be described.  FIG.  17    is a flowchart illustrating a third embodiment of processing an excess chemical liquid in the chemical liquid supply method according to the present disclosure.  FIGS.  18  to  20    are views illustrating the third embodiment of processing the excess chemical liquid in the substrate processing apparatus  100  according to the present disclosure. 
     A process of supplying a chemical liquid of a second flow rate prior to the process of processing the excess chemical liquid remains the same as or similar to that described with reference to  FIGS.  12  and  14   , so a detailed description thereof will be omitted. 
     First, the process of recovering the excess chemical liquid will be described with reference to  FIGS.  17  and  18   . 
     The excess chemical liquid remaining in a second flow rate chemical liquid supply means  250  may be introduced into an excess chemical liquid line  271  of an excess chemical liquid processing means  270 . 
     The excess chemical liquid processing means  270  may include a recovery line  274 , and a controller  290  may selectively open an excess chemical liquid valve  272  disposed on the excess chemical liquid line  271  (S 431 ) to recover the excess chemical liquid of the excess chemical liquid line  271  to the recovery line  274  (S 433 ). 
     The excess chemical liquid processing means  270  may include a storage tank  276 . The recovery line  274  may be connected to the storage tank  276 , so that recovered chemical liquid recovered to the recovery line  274  may be supplied to the storage tank  276 . The storage tank  276  may store the recovered chemical liquid temporarily or for a predetermined period of time (S 435 ). 
     In the case of the recovered chemical liquid stored in the storage tank  276  for the predetermined period of time, it may not satisfy chemical liquid supply conditions such as chemical liquid&#39;s temperature and density required for a corresponding substrate processing process. 
     Therefore, the excess chemical processing means  270  may include a circulation line  277  for circulating the recovered chemical liquid stored in the storage tank  276 . A heater (not illustrated), a pump (not illustrated), various measuring instruments (not illustrated), and the like may be disposed on the circulation line  277 . Furthermore, a new chemical liquid may be supplied to the circulation line  277 . 
     The controller  290  may adjust the recovered chemical liquid stored in the storage tank  276  to satisfy the chemical liquid supply conditions required for the recovered chemical liquid (S 437 ) while circulating the recovered chemical liquid through the circulation line  277 . 
     Next, a process of supplying the recovered chemical liquid will be described with reference to  FIGS.  17 ,  19 , and  20   . 
     Without through the circulation line  277  of the excess chemical liquid processing means  270 , the controller  290  may selectively control a recovery valve  279  to supply the recovered chemical liquid stored in the storage tank  276  to a mixing tank  215  through a recovered chemical liquid supply line  278  (S 439 ) or to a chemical liquid supply line  217  so that the recovered chemical liquid is used again. 
     As described above, since the recovered chemical liquid stored in the storage tank  276  for the predetermined period of time may not satisfy the chemical liquid supply conditions such as chemical liquid&#39;s temperature and density required for the corresponding substrate processing process, the controller  290  may adjust the recovered chemical liquid while circulating the recovered chemical liquid through the circulation line  277  (S 437 ). 
     When the recovered chemical liquid satisfies the chemical supply conditions or it is necessary to supply the recovered chemical liquid, the controller  290  may selectively open the recovery valve  279  to provide the recovered chemical liquid stored in the storage tank  276  through the recovered chemical liquid supply line  278  so that the recovered chemical liquid is used again. 
     As illustrated in  FIG.  19   , the recovered chemical liquid supply line  278  of the excess chemical liquid processing means  270  may be connected to the mixing tank  215  of a chemical liquid supply means  210 , so that the recovered chemical liquid may be supplied to the mixing tank  215  (S 439 ) to be used again through the mixing tank  215 . 
     Alternatively, as illustrated in  FIG.  20   , the recovered chemical liquid supply line  278  of the excess chemical liquid processing means  270  may be connected to the chemical liquid supply line  217  of the chemical liquid supply means  210 , so that the recovered chemical liquid of the recovery line  274  may be supplied to the chemical liquid supply line  271 . The recovery line  274  may be connected to the chemical liquid supply line  217 , so that the recovered chemical liquid of the recovery line  274  may be directly supplied to a first flow rate chemical liquid supply means  230  or the second flow rate chemical liquid supply means  250  through the chemical liquid supply line  217 . 
     As described above, the present disclosure can supply chemical liquids of different flow rates through one chemical liquid supply unit according to a substrate processing process situation. 
     In particular, a chemical liquid is supplied at the same flow rate to each of the plurality of chemical liquid lines and the flow rate of the chemical liquid is adjusted through the flow control valve disposed on at least one chemical liquid line selected among the plurality of chemical liquid lines, so that the plurality of chemical liquid lines can supply chemical liquids at different flow rates. 
     Although exemplary embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the scope and spirit of the present disclosure as disclosed in the appended claims. Therefore, exemplary embodiments of the present disclosure have not been described for limiting purposes, and the scope of the disclosure is not to be limited by the above embodiments. Therefore, the scope of the present disclosure should be determined on the basis of the descriptions in the appended claims, and all equivalents thereof should belong to the scope of the present disclosure.