Patent Publication Number: US-2023133599-A1

Title: Substrate treating apparatus and substrate treating method using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from Korean Patent Application No. 10-2021-0147103 filed on Oct. 29, 2021 in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. 119, the contents of which in its entirety are herein incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a substrate processing or treating apparatus and a substrate processing or treating method using the same. 
     2. Description of the Related Art 
     In general, manufacturing an electronic circuit component or a flat panel display (FPD) such as a liquid crystal display panel involves the formation of certain patterns such as electrodes or dots on a glass surface or a printed circuit board (PCB) by using a photoresist (PR) liquid or a paste of metal such as copper (Cu), silver (Ag), and aluminum (Al). 
     Available methods of forming a certain pattern on a PCB or substrate include taking an offset printing method using two rolls to obtain a predetermined pattern through direct patterning and a method of discharging ink droplets. Here, for the discharging of ink droplets to the substrate, an inkjet printing system works similar to an ordinary inkjet printer and uses a method of utilizing a nozzle for obtaining a predetermined pattern on the substrate through direct patterning. 
     The inkjet printing system ejects ink droplets on the substrate while moving the substrate in a predetermined direction. To discharge ink droplets to a desired position in the substrate, the substrate needs to move by a constant amount of lift. When the substrate fails to secure a constant amount of lift, ink droplets could not be accurately ejected to the desired target position. 
     SUMMARY 
     Aspects of the present disclosure provide a substrate processing or treating apparatus having improved efficiency and productivity. 
     Another aspect of the present disclosure provides a substrate treating method with improved efficiency and productivity. 
     However, aspects of the present disclosure are not restricted to those set forth herein. The above and other aspects of the present disclosure will become more apparent to one of ordinary skill in the art to which the present disclosure pertains by referencing the detailed description of the present disclosure given below. 
     According to an aspect of the present disclosure, there is provided an apparatus for treating a substrate, including a stage, a gantry, a head module, and a displacement sensor. The stage extends in the first direction, is configured to move a substrate in the first direction, and has an air floating system. The gantry is arranged on the stage to extend in a second direction crossing the first direction. The head module is installed on the gantry and movable in the second direction. The displacement sensor is installed in the head module and configured to measure the separation distance between the substrate and the stage. Here, at a first position, the head module ejects ink to the substrate and the displacement sensor measures a first separation distance between the substrate and the stage, and at a second position that is different from the first position, the head module ejects ink to the substrate and the displacement sensor measures a second separation distance between the substrate and the stage. 
     In some embodiments, the substrate treating apparatus is configured to perform maintenance and/or repair of the stage when the first separation distance differs from the second separation distance by a difference that exceeds a preset value. 
     In some embodiments, the head module includes a nozzle unit configured to discharge the ink toward the substrate, and a distance in height direction between the stage and the nozzle unit is equal to a distance in height direction between the stage and the displacement sensor. 
     The substrate treating apparatus may further include a gripper installed on one side of the stage and configured to grip the substrate. 
     In some embodiments, the displacement sensor is configured to measure the flatness of the gripper. 
     In some embodiments, the first position and the second position are spaced apart from each other in the second direction. 
     The substrate treating apparatus may further include a control module capable of monitoring the first separation distance and the second separation distance in real time. 
     In some embodiments, the stage includes two first regions and a second region between the first regions, of which the second region of the stage is overlapped by the first position and the second position. 
     In some embodiments, the first regions each constitute an area configured to eject air toward the substrate, and the second region constitutes an area configured to eject air toward the substrate and suck air between the substrate and the stage. 
     According to another aspect of the present disclosure, there is provided an apparatus for treating a substrate, including a stage, a gripper, a gantry, a head module, and a displacement sensor. The stage extends in the first direction, is configured to move a substrate in the first direction, and has an air floating system. The gripper is installed on one side of the stage to grip the substrate. The gantry is arranged on the stage to extend in a second direction crossing the first direction. The head module is installed on the gantry and movable in the second direction. The displacement sensor is installed in the head module and configured to measure the separation distance between the substrate and the stage. Herein, at a first position, the head module ejects ink to the substrate and the displacement sensor measures a first separation distance between the substrate and the stage, at a second position that is different from the first position, the head module ejects ink to the substrate and the displacement sensor measures a second separation distance between the substrate and the stage, and at a third position that is different from the first position and the second position, the displacement sensor measures the flatness of the gripper. 
     In some embodiments, the first position and the second position are spaced apart from each other in the second direction. 
     The substrate treating apparatus may further include a control module capable of monitoring the first separation distance and the second separation distance in real time. 
     In some embodiments, the stage includes two first regions and a second region between the first regions, of which the second region of the stage is overlapped by the first position and the second position. 
     In some embodiments, the first regions each constitute an area configured to eject air toward the substrate, and the second region constitutes an area configured to eject air toward the substrate and suck air between the substrate and the stage. 
     In some embodiments, the head module includes a nozzle unit configured to discharge the ink toward the substrate, and a distance in height direction between the stage and the nozzle unit is equal to a distance in height direction between the stage and the displacement sensor. 
     According to yet another aspect of the present disclosure, there is provided a method of treating a substrate, including providing a stage extending in a first direction and moving a substrate in the first direction, providing a head module arranged on the stage to be movable in a second direction crossing the first direction, causing, at a first position, a displacement sensor that is installed in the head module to measure a first separation distance between the substrate and the stage, causing, at a second position different from the first position, the displacement sensor to measure a second separation distance between the substrate and the stage, and monitoring a difference between the first separation distance and the second separation distance. 
     The substrate treating method may further include performing maintenance and/or repair of the stage when the first separation distance differs from the second separation distance by a difference that exceeds a preset value. 
     The substrate treating method may further include causing, at a third position different from the first position and the second position, the displacement sensor to measure a third separation distance between the substrate and the stage. 
     The substrate treating method may further include monitoring differences between the first separation distance, the second separation distance, and the third separation distance. 
     In some embodiments, the head module includes a nozzle unit configured to discharge the ink toward the substrate, and a distance in height direction between the stage and the nozzle unit is equal to a distance in height direction between the stage and the displacement sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects and features of the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: 
         FIG.  1    is a schematic plan view of a substrate treating apparatus according to some embodiments of the present disclosure. 
         FIG.  2    is a diagram for illustrating a stage of  FIG.  1   . 
         FIG.  3    is a cross-sectional view taken along line A-A and line B-B of  FIG.  2   . 
         FIGS.  4  and  5    are cross-sectional views of an example substrate treating apparatus taken along a second direction, according to some embodiments. 
         FIG.  6    is a cross-sectional view of an example substrate treating apparatus taken along a first direction, according to some embodiments. 
         FIG.  7    is a flowchart for describing an example substrate treating method according to some embodiments. 
         FIGS.  8  to  13    are diagrams for explaining a method of operating a substrate treating apparatus according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Advantages and features of the present disclosure and methods of accomplishing the same may be understood more readily by reference to the following detailed description of exemplary embodiments and the accompanying drawings. The present disclosure may, however, be embodied in many 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 concept of the disclosure to those skilled in the art, and the present disclosure will only be defined by the appended claims. 
     It will also be understood that when an element or a layer is referred to as being “on” another element or layer, it can be not only directly on the other element or layer, but also indirectly thereon with intervening elements or layers being present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
     Spatially relative terms, such as “below,” “beneath,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to convey one element&#39;s or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, when a device in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the illustrative term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may be interpreted accordingly. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, and/or sections, these elements, components, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, or section from another element, component, or section. Thus, a first element, first component, or first section discussed below could be termed a second element, second component, or second section without departing from the teachings of the present disclosure. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. 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. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” 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. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, like reference numerals designate like elements, although the elements are shown in different drawings. Further, in the following description of some embodiments, a detailed description of related known components and functions when considered to obscure the subject of the present disclosure will be omitted for the purpose of clarity and for brevity. 
     Hereinafter, a substrate treating apparatus according to some embodiments will be described with reference to  FIGS.  1  to  6   . The substrate treating apparatus according to some embodiments may be an inkjet printing system. 
       FIG.  1    is a schematic plan view of a substrate treating apparatus according to some embodiments of the present disclosure.  FIG.  2    is a diagram for illustrating a stage  110  of  FIG.  1   .  FIG.  3    is a cross-sectional view taken along line A-A and line B-B of  FIG.  2   . 
     Referring first to  FIG.  1   , a substrate treating apparatus according to some embodiments may include a stage  110 , a gantry  200 , a head module  300 , a gripper  400 , a transfer rail  500 , and a controller or control module  600 . 
     The stage  110  is an area for supporting and moving the substrate  150 . A method of moving the substrate  150  on the stage  110  is not limited to a specific one. The present specification illustrates a substrate treating apparatus in which the gripper  400  holds and moves the substrate  150 , but the present disclosure is not limited thereto. For example, the substrate  150  may be moved by a plate moving in a roll-to-roll manner. 
     The stage  110  may extend in a first direction X. For example, the stage  110  may include a short side extending in a second direction Y and a long side extending in the first direction X. In this specification, the first direction X and the second direction Y may be directions crossing each other. A third direction Z may be crossing the first direction X and the second direction Y. For example, the first direction X, the second direction Y, and the third direction Z may be substantially perpendicular to each other. 
     On the stage  110 , the substrate  150  may be moved along the first direction X. Here, the substrate  150  may be a transparent substrate (e.g., a glass substrate) used in a display device. For example, the substrate  150  may be a glass substrate for mass production. 
     Referring to  FIGS.  2  and  3   , the stage  110  may include two first regions I and a second region II. The second region II may be interposed between the first regions I. In particular, the first regions I may each be disposed in an edge region of the stage  110 , and the second region II may be disposed in a central region of the stage  110 . 
     For example, the stage  110  may include an air floating system. More particularly, the stage  110  may be an air floating system including the first regions I and the second region II. The first regions I and the second region II of the stage  110  may be continuous. However, the technical idea of the present disclosure is not limited thereto. Additionally, in the present specification, the second region II is illustrated as being interposed between the first regions I, but the present disclosure is not limited thereto. In some embodiments, one first region I may be disposed on one side of the stage  110  and one region II may be disposed on the other side thereof. 
     The first regions I of the stage  110  may be regions adapted to eject air in the third direction Z. The first regions I of the stage  110  may be regions for holding from sucking air on the first regions I. The first regions I may be regions adapted to load or unload the substrate  150  on or from the stage  110 . The first regions I may be regions where no printing process is performed. The printing process may be a process of discharging ink to the substrate  150 . For example, the first regions I may be regions where the head module  300  does not discharge ink toward the substrate  150 . 
     The second region II of the stage  110  may be a region adapted to eject air in the third direction Z while sucking air on the second region II. For example, the second region II of the stage  110  may be a region that sucks air between the substrate  150  and the stage  110  while ejecting air toward the substrate  150 . Additionally, the second region II may be a region in which a printing process is performed. The second region II may be a region in which the head module  300  discharges ink toward the substrate  150 . 
     In some embodiments, the stage  110  may include a plurality of holes  110 H. The hole  110 H may be a hole for ejecting air or a hole for sucking air. For example, the first regions I of the stage  110  may have just the holes for ejecting air. The second region II of the stage  110  may have an alternate arrangement of holes for ejecting air and holes for sucking air. 
     In  FIG.  3   , the hole  110 H of the stage  110  may include first holes  110 H_ 1  and second holes  110 H_ 2 . The first holes  110 H_ 1  may be holes for ejecting air. The second holes  110 H_ 2  may be the holes for sucking air. 
     The second region II of the stage  110  may include the first holes  110 H_ 1  for ejecting air upward and the second holes  110 H_ 2  for sucking air. Although the first holes  110 H_ 1  and the second holes  110 H_ 2  are illustrated as being alternately arranged, the present disclosure is not limited thereto. The first regions I of the stage  110  may include only the first holes  110 H_ 1  for ejecting air upward. 
     Referring back to  FIG.  1   , the transport rail  500  may be disposed on one side of the stage  110 . The transfer rail  500  may extend lengthwise in the first direction X. The transfer rail  500  allows moving the substrate  150  in the first direction X. For example, the gripper  400  may grip one side of the substrate  150  and move along the transfer rail  500 . With the gripper  400  holding the substrate  150  and moving in the first direction X along the transfer rail  500 , the substrate  150  moves in the first direction X along the transfer rail  500 . 
     The gripper  400  may be disposed on one side of the substrate  150  to grip the substrate  150 . The gripper  400  may be coupled to the transfer rail  500  to move in the first direction X. The gripper  400  may grip and transfer the substrate  150 . The gripper  400  may hold the substrate  150  by suction. The substrate  150  may include a grip portion  150   a  that is adhered by suction to the gripper  400 . The grip portion  150   a  may be on one side of the substrate  150 . For example, when the substrate  150  includes long sides extending in the first direction X and short sides extending in the second direction Y, the grip portion  150   a  may be one of the long sides of the substrate  150 . Then, the gripper  400  may hold by suction one of the long sides of the substrate  150 . 
     The gantry  200  may be disposed on the stage  110  to cross thereof. The gantry  200  may extend lengthwise in the second direction Y, for example. The gantry  200  may be disposed on the second region II of the stage  110 . 
     The head module  300  may be installed on the gantry  200  and move along the gantry  200 . The head module  300  may move in the second direction Y, but is not limited thereto. 
     In some embodiments, although not shown, when the head module  300  is in its movement in the second direction Y, a distance in the third direction Z or height direction between the substrate  150  and the head module  300  may become smaller. In other words, when in its standby state, the head module  300  may be distanced from the substrate  150  by a greater distance in the third direction Z or height direction than the distance in height direction between the substrate  150  and the head module  300  when in its movement. When the head module  300  is in its movement, as the substrate  150  and the head module  300  come closer together, a nozzle unit  320  in  FIG.  4    of the head module  300  may eject ink accurately toward the substrate  150 . 
     The control module  600  may monitor the separation distance between the substrate  150  and the stage  110  in real time. The control module  600  may monitor the flatness of the gripper  400  in real time. The control module  600  may monitor the separation distance and the flatness to determine whether to perform maintenance and/or repair of the stage  110  and the gripper  400 . 
       FIGS.  4  and  5    are cross-sectional views of an example substrate treating apparatus taken along the second direction, according to some embodiments.  FIG.  6    is a cross-sectional view of an example substrate treating apparatus taken along the first direction, according to some embodiments. 
     The following describes a substrate treating apparatus and an exemplary operation method of the substrate treating apparatus according to some embodiments in more detail with reference to  FIGS.  4  to  6   . 
     Referring to  FIGS.  4  to  6   , the head module  300  may include a body  310 , a nozzle unit  320 , and a displacement sensor  330 . The body  310  may be a part linked to the gantry  200 . The body  310  may be fixed to the gantry  200 . The body  310  may fix the nozzle unit  320  and the displacement sensor  330 . The nozzle unit  320  may be a part that discharges ink toward the substrate  150 . The displacement sensor  330  may be a sensor that measures the amount of floating of the substrate  150 . 
     In some embodiments, the nozzle unit  320  may include multiple nozzles. The ink discharged by the head module  300  may be, for example, Quantum Dot (QD) ink, but is not limited thereto. The multiple nozzles of the nozzle unit  320  may eject a plurality of ink droplets to the substrate  150  as indicated by an arrow  325 . 
     In some embodiments, the displacement sensor  330  may measure the amount of floating of the substrate  150  as indicated by an icon  335 . The floating amount of the substrate  150  may represent a separation distance d of the substrate  150  from the stage  110  in the third direction Z. The displacement sensor  330  may measure and transmit the amount of floating of the substrate  150  to the control module  600 . The control module  600  may monitor the amount of floating of the substrate  150  in real time. The control module  600  may monitor the amount of floating of the substrate  150  to determine whether to perform maintenance and/or repair of the substrate treating apparatus according to some embodiments. 
     For example, the present disclosure in some embodiments measures, in a first position, the floating amount of the substrate  150 , measures, in a second position, the floating amount of the substrate  150 , and monitors a difference between the two floating amounts. When the difference between the two floating amounts exceeds a preset value, the substrate treating apparatus may maintain and/or repair the stage  110 . 
     More specifically, the stage  110  having an air floating system may include a precision floating area. For example, a region where the head module  300  discharges ink toward the substrate  150  may be a precision floating region (e.g., the second region of  FIG.  2   ). In the precision floating area, the amount of floating of the substrate  150  needs to be constant for allowing ink to be accurately discharged. The displacement sensor  330  may measure the amount of floating of the board  150  in real time and transmit the measured floating amount to the control module  600  which may then monitor the floating amount in real time. When the result of real-time monitoring exhibits an inconsistent floating amount of the substrate  150 , the substrate treating apparatus may perform the maintenance and/or repair work. 
     In some embodiments, ejecting ink to the substrate  150  by the nozzle unit  320  and measuring the floating amount of the substrate  150  by the displacement sensor  330  may be simultaneously performed. Additionally, the distance in the third direction Z from the substrate  150  to the displacement sensor  330  may be equal to the distance in the third direction Z from the substrate  150  to the head module  300  or the substrate  150  or equal to the distance in the third direction Z from the substrate  150  to the nozzle unit  320 . Accordingly, the conditions for discharging ink to the substrate  150  may be the same as the conditions for measuring the floating amount of the substrate  150 . 
     In some embodiments, the displacement sensor  330  may measure the flatness of the gripper  400 . Measuring the flatness of the gripper  400  may mean measuring the flatness of the substrate  150  held by the gripper  400 , but is not limited thereto. 
     In  FIG.  4   , when the displacement sensor  330  is positioned to overlap the substrate  150  in the third direction Z, the displacement sensor  330  may measure the separation distance d between the substrate  150  and the stage  110 . 
     In  FIG.  5   , when the displacement sensor  330  is positioned to overlap the grip portion  150   a  of the substrate  150  in the third direction Z, the displacement sensor  330  may measure the flatness of the gripper  400 . 
     In  FIG.  6   , while the displacement sensor  330  measures the separation distance d between the substrate  150  and the stage  110 , the substrate  150  may be moved in the first direction X as indicated by the arrow  151 . In this way, as the substrate  150  moves in the first direction X, the separation distance d between the substrate  150  and the stage  110  may be continuously measured along the first direction X. 
     The following describes a substrate treating method according to some embodiments with reference to  FIGS.  7  to  13   . 
       FIG.  7    is a flowchart for describing an example substrate treating method according to some embodiments.  FIGS.  8  to  13    are diagrams for explaining a method of operating a substrate treating apparatus according to some embodiments. 
     Referring to  FIG.  7   , the substrate treating method according to some embodiments may include loading a substrate onto the stage (S 100 ), measuring, in a first position, a first separation distance between the substrate and the stage (S 200 ), moving the head module to a second position (S 300 ), measuring, in a first second, a second separation distance between the substrate and the stage (S 400 ), and monitoring the difference the first separation distance and the second separation distance (S 500 ). 
     Referring to  FIGS.  7  and  8   , the substrate  150  may be loaded onto the stage  110  (S 100 ). 
     The substrate  150  may be loaded onto one of the first regions I of the stage  110 . The substrate  150  may be loaded while moving in the first direction X as indicated by arrow  151 . The gripper  400  does not grip the substrate  150  until the same is completely loaded. When the substrate  150  is completely loaded, the gripper  400  may grip and align the substrate  150 . Although not shown, the substrate  150  may include alignment marks. The substrate treating apparatus may align the substrate  150  by using the alignment marks. Aligning the substrate  150  may include aligning the substrate  150  in parallel with a plane extending in the first direction X and the second direction Y, and aligning the substrate  150  to have its long side extend in parallel with the first direction X. 
     Referring to  FIG.  9   , the substrate  150  may be moved from the first region Ito the second region II as indicated by arrow  151 . 
     The substrate  150  moves in the first direction X into the second region II. Specifically, the gripper  400  grips the grip portion  150   a  of the substrate  150 . Thereafter, the gripper  400  moves in the first direction X along the transfer rail  500 . With the gripper  400  holding the substrate  150 , when the gripper  400  moves, the substrate  150  can come along. 
       FIG.  10    is a plan view of a substrate in accordance with some embodiments. 
     Referring to  FIG.  10   , the substrate  150  may include first to fourth positions P 1 , P 2 , P 3 , and P 4 . The second, third, and fourth positions P 2 , P 3 , P 4  in the substrate  150  may represent positions occupied by the displacement sensor  330  (in  FIG.  4   ) when moving in the second direction Y to measure the amount of floating of the substrate  150 . The first position P 1  may represent a position occupied by the displacement sensor  330  when moving in the second direction Y to measure the flatness of the gripper  400 . Hereinafter, a method of operating a substrate treating apparatus according to some embodiments will be described in more detail. 
     Referring to  FIGS.  10  and  11   , the head module  300  may move to the first position P 1 . 
     The head module  300  moving to the first position P 1  may mean the movement of the displacement sensor  330  of the head module  300  to a position where the displacement sensor  330  overlaps the first position P 1  in the third direction Z. The first position P 1  may overlap the grip portion  150   a  of the substrate  150  in the first direction X. The first position P 1  may extend in the first direction X on the grip portion  150   a  of the substrate  150 . 
     Then, the displacement sensor  330  measures the flatness of the gripper  400  as indicated by the icon  335 . While the substrate  150  moves in the first direction X, the displacement sensor  330  may continuously measure the flatness of the gripper  400 . 
     While the displacement sensor  330  measures the flatness of the gripper  400 , the nozzle unit  320  may eject ink to the substrate  150  as indicated by arrow  325 . This means that ejecting ink to the substrate  150  by the nozzle unit  320  and measuring the flatness of the gripper  400  by the displacement sensor  330  may proceed simultaneously. 
     Referring to  FIGS.  10  and  12   , the head module  300  may move to the second position P 2  as indicated by the arrow  301 . The second position P 2  may be overlapped by the displacement sensor  330  of the head module  300  in the third direction Z. The second position P 2  may extend in the first direction X on the substrate  150 . 
     The displacement sensor  330  may measure, in the second position P 2 , a first separation distance dl between the substrate  150  and the stage  110  (Step S 200  in  FIG.  7   ). The first separation distance d 1  may mean a separation distance measured in the third direction Z between the substrate  150  and the stage  110 . The first separation distance d 1  may be a floating amount of the substrate  150  at the second position P 2 . 
     In the second position P 2 , while the displacement sensor  330  measures the flatness of the gripper  400  as indicated by the icon  335 , the nozzle unit  320  may eject ink to the substrate  150  as indicated by arrow  335 . In other words, the ejecting of ink to the substrate  150  by the nozzle unit  320  and the measuring of the amount of floating of the substrate  150  by the displacement sensor  330  may proceed concurrently. 
     Referring to  FIGS.  10  and  13   , the head module  300  may move to the third position P 3  (Step S 300  in  FIG.  7   ). 
     In particular, the head module  300  may move in the second direction Y from the second position P 2  to the third position P 3  as indicated by the arrow  301 . The third position P 3  may be overlapped by the displacement sensor  330  of the head module  300  in the third direction Z. The third position P 3  may extend in the first direction X on the substrate  150 . 
     The displacement sensor  330  may measure a second separation distance d 2  between the substrate  150  and the stage  110  at the third position P 3  (S 400  of  FIG.  7   ). The second separation distance d 2  may mean a separation distance measured in the third direction Z between the substrate  150  and the stage  110 . The second separation distance d 2  may be a floating amount of the substrate  150  at the third position P 3 . 
     In the third position P 3 , while the displacement sensor  330  measures the flatness of the gripper  400  as indicated by the icon  335 , the nozzle unit  320  may eject ink to the substrate  150  as indicated by the arrow  325 . In other words, the ejecting of ink to the substrate  150  by the nozzle unit  320  and the measuring of the amount of floating of the substrate  150  by the displacement sensor  330  may proceed concurrently. 
     Although not shown, the head module  300  may move to the fourth position P 4 . The head module  300  may move in the second direction Y as indicated by the arrow  301 . At the fourth position P 4  in the substrate  150 , the displacement sensor  330  may measure a third separation distance between the substrate  150  and the stage  110 . Although the present specification describes measuring the separation distances between the substrate  150  and the stage  110  at the second, third, and fourth positions P 2 , P 3 , P 4 , the technical idea of the present disclosure is not limited thereto. 
     Subsequently, the control module  600  ( FIG.  1   ) may monitor the difference between the first separation distance d 1  and the second separation distance d 2  (S 500  in  FIG.  7   ). When the difference between the first separation distance d 1  and the second separation distance d 2  is close to 0, the substrate treating apparatus may determine that the floating amount of the substrate  150  is constant. However, at the occurrence of a difference between the first separation distance dl and the second separation distance d 2 , the substrate treating apparatus may determine that the floating amount of the substrate  150  is inconstant. When the floating amount of the substrate  150  is inconstant, the efficiency and accuracy of the printing process may be reduced. In this case, the substrate treating apparatus needs to be maintained and/or repaired. 
     The substrate treating apparatus according to some embodiments may maintain and/or repair the stage  110  responsive to when the difference between the first separation distance d 1  and the second separation distance d 2  exceeds a preset value. The present disclosure in some embodiments can provide a substrate treating apparatus with improved efficiency and reliability by monitoring the amount of floating of the substrate  150  in real time, and a substrate treating method using the same. 
     In some embodiments, when the displacement sensor  330  measures at ‘n’ positions, ‘n’ separation distances, the control module  600  may monitor the differences between two respective ones of the ‘n’ separation distances. The more the measured separation distances, the more accurate result can be obtained when determining whether the floating amount of the substrate  150  is constant. 
     While a few exemplary embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art will readily appreciate that various changes in form and details may be made therein without departing from the technical idea and scope of the present disclosure as defined by the following claims. Therefore, it is to be understood that the foregoing is illustrative of the present disclosure in all respects and is not to be construed as limited to the specific exemplary embodiments disclosed.