Patent Publication Number: US-2022234948-A1

Title: Substrate loading cassette and method of processing substrate using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 of Korean Patent Application No. 10-2021-0009626, filed on Jan. 22, 2021, the contents of which are incorporated by reference herein in their entirety. 
     BACKGROUND 
     1. Field of Disclosure 
     The present disclosure relates to a substrate loading cassette with improved reliability and a method of processing a substrate using the same. 
     2. Description of the Related Art 
     Display devices are used to convey information to a user. Display devices may be included in products such as television sets, mobile phones, navigation units, computer monitors, game units, or the like. Display devices may include fragile substrates and may be made of glass which is brittle and easily damaged. 
     During the manufacturing process, substrates can be subjected to a reinforcing process to improve surface hardness, impact resistance, and workability. The reinforcing process can include both physical reinforcing and chemical reinforcing. A cassette to load the substrates may be used to facilitate the storage and transfer of the substrates during the reinforcing process. 
     Traditionally, the cassettes are fixed, and the substrate is provided to the cassettes using a robotic arm. However, variables such as the robotic arm and the thickness of the substrate are not taken into account during the manufacturing process. This can lead to inaccuracy and damage to the substrate. Therefore, there is a need in the art to for an improved display device manufacturing process. 
     SUMMARY 
     The present disclosure describes a substrate loading cassette with improved reliability. The present disclosure also describes a method of processing a substrate using the substrate loading cassette. 
     Embodiments of the inventive concept include a substrate loading cassette including a first frame, a second frame facing the first frame and spaced apart from the first frame in a first direction, a first supporter coupled with the first frame, and a second supporter movably coupled with the first frame and disposed under the first supporter. 
     The first supporter includes a first support bar coupled with the first frame and extending in a second direction crossing the first direction and a plurality of first branch portions protruding from the first support bar toward the second frame, and the second supporter includes a second support bar coupled with the first frame and extending in the second direction and a plurality of second branch portions protruding from the second support bar toward the second frame. The second branch portions move in a direction substantially parallel to the second direction. 
     The first branch portions do not overlap the second branch portions when viewed in a third direction crossing the first direction and the second direction. The second branch portions are operated in a first state or a second state, a maximum distance in the second direction between one first branch portion among the first branch portions and one second branch portion adjacent to the one first branch portion among the second branch portions has a first distance in the first state when viewed in the third direction crossing the first direction and the second direction, the maximum distance has a second distance in the second state, and the first distance is greater than the second distance. 
     Each of the first branch portions protrude from the first support bar to a direction that is substantially parallel to a first crossing direction crossing the first direction and the second direction, and each of the second branch portions protrude from the second support bar to a direction that is substantially parallel to a second crossing direction crossing the first crossing direction. 
     A distance between one first branch portion among the first branch portions and one second branch portion adjacent to the one first branch portion among the second branch portions increases going from the first frame to the second frame. Each of the first branch portions protrude from the first support bar to a direction substantially parallel to the first direction, and each of the second branch portions protrude from the second support bar to a direction substantially parallel to the first direction. 
     The substrate loading cassette further includes a third supporter coupled with the second frame and a fourth supporter movably coupled with the second frame and disposed under the third supporter. The third supporter includes a third support bar coupled with the second frame and extending in the second direction and a plurality of third branch portions protruding from the third support bar toward the first frame. The fourth supporter includes a fourth support bar coupled with the second frame and extending in the second direction and a plurality of fourth branch portions protruding from the fourth support bar toward the first frame. 
     The fourth branch portions move in the direction substantially parallel to the second direction. A distance between one third branch portion among the third branch portions and one fourth branch portion adjacent to the one third branch portion among the fourth branch portions is substantially simultaneously controlled to correspond to a distance between one first branch portion among the first branch portions and one second branch portion adjacent to the one first branch portion among the second branch portions. 
     The first branch portions respectively face the third branch portions in the first direction, and the second branch portions respectively face the fourth branch portions in the first direction. The first frame, the second frame, the first supporter, and the second supporter include a stainless steel. 
     Embodiments of the inventive concept provide a method of processing a substrate. The method of processing the substrate includes providing a cassette including a first frame, a second frame spaced apart from the first frame in a first direction, a first support bar coupled with the first frame and extending in a second direction crossing the first direction, a first branch portion protruding from the first support bar toward the second frame, a second support bar disposed under the first support bar, and a second branch portion protruding from the second support bar toward the second frame, fixing a substrate to a robot arm, adjusting a distance in a direction substantially parallel to the second direction between the first branch portion and the second branch portion to a first distance when viewed in a third direction crossing the first direction and the second direction, loading the substrate between the first frame and the second frame, adjusting the distance to a second distance smaller than the first distance, and reinforcing the substrate. 
     A maximum distance of the first distance is greater than a width in the second direction of the robot arm. A maximum distance of the second distance is greater than a thickness of the substrate in the direction substantially parallel to the second direction. A maximum distance of the second distance is smaller than a width in the second direction of the robot arm. 
     The adjusting of the distance to the first distance includes moving the second branch portion in the direction substantially parallel to the second direction. The adjusting of the distance to the second distance includes moving the second branch portion in the direction substantially parallel to the second direction. 
     The reinforcing of the substrate includes preheating the cassette and the substrate, chemically reinforcing the cassette and the substrate, and cooling the cassette and the substrate. The first branch portion protrudes from the first support bar to a direction substantially parallel to a first crossing direction crossing the first direction and the second direction, and the second branch portion protrudes from the second support bar to a direction substantially parallel to a second crossing direction crossing the first crossing direction. The first branch portion protrudes from the first support bar to a direction substantially parallel to the first direction, and the second branch portion is substantially parallel to the first branch portion. 
     According to the above, the substrate fixed to the robot arm is disposed between the first branch portion and the second branch portion of the cassette, and the distance between the first branch portion and the second branch portion is adjusted by taking into account a size of the robot arm. Therefore, the reliability of an automated process using the robot arm is improved, and damage occurring to the substrate when loading the substrate are reduced. After the substrate is loaded into the cassette, the distance between the first branch portion and the second branch portion is adjusted again by taking into account the thickness of the substrate. Then, the substrate is prevented from shaking in the process of reinforcing the substrate. Therefore, the substrate is prevented from being damaged. Accordingly, the reliability of the substrate loading cassette and the method of processing the substrate using the substrate loading cassette is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other advantages of the present disclosure will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a perspective view showing a substrate loading cassette according to an embodiment of the present disclosure; 
         FIG. 2  is a flowchart showing a method of processing a substrate according to an embodiment of the present disclosure; 
         FIG. 3A  is a plan view showing a substrate loading cassette according to an embodiment of the present disclosure; 
         FIG. 3B  is a plan view showing a substrate loading cassette according to an embodiment of the present disclosure; 
         FIG. 4  is a side view showing a substrate loading cassette according to an embodiment of the present disclosure; 
         FIG. 5A  is a plan view showing a substrate loading cassette according to an embodiment of the present disclosure; 
         FIG. 5B  is a plan view showing a substrate loading cassette according to an embodiment of the present disclosure; 
         FIG. 6  is a flowchart showing a process of reinforcing a substrate according to an embodiment of the present disclosure; and 
         FIG. 7  is a view showing a process of chemically reinforcing a substrate according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates generally to a substrate loading cassette. More particularly, embodiments of the present disclosure relate to a substrate loading cassette capable of adjusting the branches of the substrate loading cassette to take into account the thickness of the substrate. In some embodiments, the present disclosure adjusts the distance between a first branch portion and a second branch portion by taking into account a size of the robot arm and the substrate. 
     Conventional substrate loading cassettes used a fixed substrate which is attached to a robot arm, where the robot arm is located between a first branch portion and a second branch portion of the cassette. The distance between the first branch portion and the second branch portion is not adjusted by taking into account a size of the robot arm. As such, damage to the substrate is possible and reliability is reduced. 
     An embodiment of the substrate loading cassette of the present disclosure includes a first frame, a second frame, a first supporter coupled with the first frame, and a second supporter movably coupled with the first frame and disposed under the first supporter. The first supporter includes a first support bar and a plurality of first branch portions, and the second supporter includes a second support bar and a plurality of second branch portions. The second branch portions move in a second direction to adjust the spacing between the first and second supporters. 
     In the present disclosure, it will be understood that when an element or layer is referred to as being “on”, “connected to” or “coupled to” another element or layer, the element or layer can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. 
     Like numerals refer to like elements throughout. In the drawings, the thickness, ratio, and dimension of components are exaggerated for effective description of the technical content. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, a first element discussed below could be termed a second element without departing from the teachings 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. 
     Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. 
     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 disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as with 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. 
     It will be further understood that the terms “includes” and/or “including”, when used in this specification, 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. 
     Hereinafter, the present disclosure will be explained in detail with reference to the accompanying drawings. 
       FIG. 1  is a perspective view showing a substrate loading cassette CST according to an embodiment of the present disclosure. 
     Referring to  FIG. 1 , the substrate loading cassette CST may include a first frame FR 1 , a second frame FR 2 , a first supporter SP 1 , a second supporter SP 2 , a third supporter SP 3 , and a fourth supporter SP 4 . 
     The first frame FR 1  and the second frame FR 2  may face each other. The second frame FR 2  may be spaced apart from the first frame FR 1  in a first direction DR 1 .The first supporter SP 1  may be coupled with the first frame FR 1 . The first supporter SP 1  may include a first support bar SR 1  and a plurality of first branch portions BR 1 . 
     The first support bar SR 1  may extend in a second direction DR 2  crossing the first direction DR 1  (i.e., perpendicular to the first direction DR 1 ).The first branch portions BR 1  may protrude from the first support bar SR 1  toward the second frame FR 2 . 
     The second supporter SP 2  may be movably coupled with the first frame FR 1 . The second supporter SP 2  may be disposed under the first supporter SP 1 . The second supporter SP 2  may include a second support bar SR 2  and a plurality of second branch portions BR 2 . The second support bar SR 2  may extend in the second direction DR 2 . 
     The second branch portions BR 2  may protrude from the second support bar SR 2  toward the second frame FR 2 . The second branch portions BR 2  may move in a direction substantially parallel to the second direction DR 2 . A first controller CT 1  may control the movement of the second branch portions BR 2 . For example, the first controller CT 1  may control the movement of the second branch portions BR 2  using a hydraulic, pneumatic or electric actuator. In some examples, the first controller CT 1  moves the second branch portions BR 2  by moving the second support bar SR 2 . However, in other examples, the first controller CT 1  moves the second branch portions BR 2  directly without moving the second support bar SR 2 . 
     Each of the first supporter SP 1  and the second supporter SP 2  may be provided in plural. The first supporters SP 1  and the second supporters SP 2  may be alternately arranged one by one in a third direction DR 3  crossing (i.e., perpendicular to) the first direction DR 1  and the second direction DR 2 .  FIG. 1  shows three first supporters SP 1  and three second supporters SP 2  as a representative example. However, the number of the first supporters SP 1  and the number of the second supporters SP 2  should not be limited thereto or thereby. For example, two first supporters SP 1  and two second supporters SP 2  may be sequentially arranged in the third direction DR 3 . 
     The third supporter SP 3  may be coupled with the second frame FR 2 . The third supporter SP 3  may include a third support bar SR 3  and a plurality of third branch portions BR 3 . The third support bar SR 3  may be coupled with the second frame FR 2 . The third support bar SR 3  may extend in the second direction DR 2 . The third support bar SR 3  may face the first support bar SR 1  in the first direction DR 1 . 
     The third branch portions BR 3  may protrude from the third support bar SR 3  toward the first frame FR 1 . The third branch portions BR 3  may respectively face the first branch portions BR 1  in the first direction DR 1 . 
     The fourth supporter SP 4  may be movably coupled with the second frame FR 2  and may be disposed under the third supporter SP 3 . The fourth support bar SR 4  may extend in the second direction DR 2 . The fourth support bar SR 4  may face the second support bar SR 2  in the first direction DR 1 . The fourth supporter SP 4  may include a fourth support bar SR 4  and a plurality of fourth branch portions BR 4 . 
     The fourth branch portions BR 4  may protrude from the fourth support bar SR 4  toward the first frame FR 1  and may move in the direction substantially parallel to the second direction DR 2 . A second controller CT 2  may control the movement of the fourth branch portions BR 4 . For example, the second controller CT 2  may control the movement of the fourth branch portions BR 4  using a hydraulic, pneumatic or electric actuator. In some examples, the second controller CT 2  moves the fourth branch portions BR 4  by moving the fourth support bar SR 4 . However, in other examples, the second controller CT 2  moves the fourth branch portions BR 4  directly without moving the fourth support bar SR 4 . The fourth branch portions BR 4  may respectively face the second branch portions BR 2  in the first direction DR 1 . 
     Each of the third supporter SP 3  and the fourth supporter SP 4  may be provided in plural. The third supporters SP 3  and the fourth supporters SP 4  may be alternately arranged one by one in the third direction DR 3 .  FIG. 1  shows three third supporters SP 3  and three fourth supporters SP 4  as a representative example. However, the number of the third supporters SP 3  and the number of the fourth supporters SP 4  should not be limited thereto or thereby. 
     The first frame FR 1 , the second frame FR 2 , the first supporter SP 1 , the second supporter SP 2 , the third supporter SP 3 , and the fourth supporter SP 4  may include a material with heat resistance and chemical resistance. The first frame FR 1 , the second frame FR 2 , the first supporter SP 1 , the second supporter SP 2 , the third supporter SP 3 , and the fourth supporter SP 4  may include stainless steel. For example, the first frame FR 1 , the second frame FR 2 , the first supporter SP 1 , the second supporter SP 2 , the third supporter SP 3 , and the fourth supporter SP 4  may include SUS  304  or SUS  316 . 
     According to an embodiment, the first frame FR 1 , the second frame FR 2 , the first supporter SP 1 , the second supporter SP 2 , the third supporter SP 3 , and the fourth supporter SP 4  may reduce corrosion and chemical reactions that may occur in the cassette CST in a substrate processing process. Additionally or alternatively, a deformation of the cassette CST, which may be caused by thermal expansion and thermal contraction generated after the repeating of the substrate processing process, may be reduced. Accordingly, the reliability of the cassette CST and the substrate processing method may be improved. 
       FIG. 2  is a flowchart showing a method of processing a substrate according to an embodiment of the present disclosure.  FIG. 3A  is a plan view showing the substrate loading cassette CST according to an embodiment of the present disclosure. 
     Referring to  FIGS. 1 to 3A , the cassette CST into which the substrate GL is loaded may be provided (S 100 ) to prevent the substrate GL from being influenced by impacts, contaminations, scratches, dust, etc., in the process of processing the substrate GL. 
     The cassette CST may include the first frame FR 1 , the second frame FR 2 , the first support bar SR 1 , the first branch portions BR 1 , the second support bar SR 2 , the second branch portions BR 2 , the third support bar SR 3 , the third branch portions BR 3 , the fourth support bar SR 4 , and the fourth branch portions BR 4 . 
     When viewed in the third direction DR 3 , each of the first branch portions BR 1  may protrude from the first support bar SR 1  to a direction that may be substantially parallel to a first crossing direction DRa crossing the first direction DR 1  and the second direction DR 2 . Each of the second branch portions BR 2  may protrude from the second support bar SR 2  to a direction that is substantially parallel to a second crossing direction DRb crossing the first crossing direction DRa. 
     When viewed in the third direction DR 3 , the first support bar SR 1  may overlap the second support bar SR 2 , and the first branch portions BR 1  may not overlap the second branch portions BR 2 . 
     When viewed in the third direction DR 3 , a distance between one first branch portion among the first branch portions BR 1  and one second branch portion among the second branch portions BR 2  adjacent to the one first branch portion may increase going from the first frame FR 1  to the second frame FR 2 . 
     When viewed in the third direction DR 3 , each of the third branch portions BR 3  may protrude from the third support bar SR 3  to a direction that is substantially parallel to a third crossing direction DRc opposite to the first crossing direction DRa. Each of the fourth branch portions BR 4  may protrude from the fourth support bar SR 4  to a direction that is substantially parallel to a fourth crossing direction DRd crossing the third crossing direction DRc and opposite to the second crossing direction DRb. 
     When viewed in the third direction DR 3 , the third support bar SR 3  may overlap the fourth support bar SR 4 , and the third branch portions BR 3  may not overlap the fourth branch portions BR 4 . 
     When viewed in the third direction DR 3 , a distance between one third branch portion among the third branch portions BR 3  and one fourth branch portion among the fourth branch portions BR 4  adjacent to the one third branch portion may increase going from the second frame FR 2  to the first frame FR 1 . 
     The substrate GL may be loaded into the cassette CST regardless of the size of the substrate GL by adjusting a distance in the first direction DR 1  between the first frame FR 1  and the second frame FR 2 . Accordingly, the cost of changing the cassette CST in accordance with the size of the substrate GL may be reduced, and the yield of the process of processing the substrate GL may be improved. 
     The substrate GL may be a glass substrate. The substrate GL may be a thin glass substrate. For example, the substrate GL may have a thickness GW equal to or smaller than about 70 micrometers (μm) in the second direction DR 2 . The substrate GL may be reinforced by a chemical processing process, and the reinforced substrate may be used as a window of the display device. 
     In the process of processing the substrate GL, a robot arm RA may be used and the substrate GL may be fixed to the robot arm RA (S 200 ). Different from the present disclosure, in a case where the substrate GL is loaded into the cassette CST or processed without using the robot arm RA, the substrate GL may be damaged or broken due to the thickness GW of the substrate GL in the process of processing the substrate GL. However, the robot arm RA is used to fix the substrate GL at constant force to prevent the substrate GL from being damaged. Therefore, the substrate GL may be easily processed. Accordingly, the reliability of the substrate processing method may be improved. 
     The robot arm RA may automate the process of processing the substrate GL. The robot arm RA may reduce the number of people and time used in the process of processing the substrate GL and may improve the yield. 
     The robot arm RA may be provided in plural. The robot arms RA may be arranged in the first direction DR 1  to fix the substrate GL.  FIG. 3A  shows three robot arms RA as a representative example. However, the number of the robot arms RA should not be particularly limited as long as the robot arms RA may fix the substrate GL. For example, two robot arms RA may be used, and the robot arms RA may be disposed respectively adjacent to the first frame FR 1  and the second frame FR 2  to fix the substrate GL. 
     The first controller CT 1  may move one second branch portion BR 2  (hereinafter, referred to as a second branch portion BR 2 ) among the second branch portions BR 2  in the direction that is substantially parallel to the second direction DR 2 . The first controller CT 1  may control a distance in the direction that is substantially parallel to the second direction DR 2  between one first branch portion BR 1  (hereinafter, referred to as a first branch portion BR 1 ), which may be adjacent to the second branch portion BR 2 , among the first branch portions BR 1  and the second branch portion BR 2 . When viewed in the third direction DR 3 , a maximum distance in the direction that is substantially parallel to the second direction DR 2  between the first branch portion BR 1  and the second branch portion BR 2  may be adjusted to a first distance BW 1   a  (S 300 ), e.g., using an actuator. The cassette CST in which the distance is adjusted to the first distance BW 1   a  may be referred to as operating in a first state. 
     In some examples, size information for the substrate GL is provided to a controller which determines the distance between branch portions (or the operating state of the cassette CST). For example, if the width of the substrate is greater than a threshold width, the distance between the first branch portion BR 1  and the second branch portion BR 2  can be increased. Additionally or alternatively, if the width of the substrate is below a threshold, the distance between the first branch portion BR 1  and the second branch portion BR 2  can be decreased. In another example, the distance can be calculated based on a linear relationship between the distance and the width of the substrate. However, the present disclosure is not limited to these examples for determining the distance between the first branch portion BR 1  and the second branch portion BR 2 . Thus, in some examples the distance between the first branch portion BR 1  and the second branch portion BR 2  can be adjusted based on the width of the substrate. 
     Additionally or alternatively, the distance between the first branch portion BR 1  and the second branch portion BR 2  can be adjusted based on the size of the robot arm that moves the substrate GL into the cassette CST. For example, information regarding the size of the robot arm can be provided to a controller, which computes the distance to enable safe operation of the robot arm to load the substrate GL into the cassette CST. 
     The first distance BW 1   a  may be greater than a width RW in the direction that is substantially parallel to the second direction DR 2  of the robot arm RA. Accordingly, when the substrate GL is loaded, the robot arm RA may be prevented from colliding or interfering with the first branch portion BR 1  and the second branch portion BR 2 . 
     When the robot arm RA loads the substrate GL, the robot arm RA may be spaced apart from the first branch portion BR 1  and the second branch portion BR 2 . When viewed in the third direction DR 3 , the robot arm RA may easily insert the substrate GL between the first branch portion BR 1  and the second branch portion BR 2 . Accordingly, the reliability of the substrate processing method may be improved. 
     When viewed in the third direction DR 3 , a minimum distance in the direction that may be substantially parallel to the second direction DR 2  between the first branch portion BR 1  and the second branch portion BR 2  may be a first minimum distance BW 2   a . The first minimum distance BW 2   a  may be greater than the thickness GW of the substrate GL. 
     When the robot arm RA loads the substrate GL, the substrate GL may be spaced apart from the first branch portion BR 1  and the second branch portion BR 2 . When viewed in the third direction DR 3 , the substrate GL may be easily inserted into between the first branch portion BR 1  and the second branch portion BR 2 . 
     When viewed in the third direction DR 3 , the second controller CT 2  may move one fourth branch portion BR 4  (hereinafter, referred to as a fourth branch portion BR 4 ) among the fourth branch portions BR 4  in the direction that may be substantially parallel to the second direction DR 2 . The second controller CT 2  may control a distance in the direction that is substantially parallel to the second direction DR 2  between one third branch portion BR 3  (hereinafter, referred to as a third branch portion BR 3 ), which may be adjacent to the fourth branch portion BR 4 , among the third branch portions BR 3  and the fourth branch portion BR 4 . The distance in the direction that is substantially parallel to the second direction DR 2  between the third branch portion BR 3  and the fourth branch portion BR 4  may be substantially simultaneously controlled to correspond to the distance in the direction that is substantially parallel to the second direction DR 2  between the first branch portion BR 1  and the second branch portion BR 2 . 
     The substrate GL fixed to the robot arm RA may be loaded into the cassette CST (S 400 ). The substrate GL may be provided in plural and may be loaded into the cassette CST. The substrates GL may be spaced apart from each other in the direction that is substantially parallel to the second direction DR 2  while being loaded into the cassette CST. 
       FIG. 3B  is a plan view showing a substrate loading cassette CST- 1  according to an embodiment of the present disclosure. In  FIG. 3B , the same reference numerals denote the same elements in  FIG. 3A . Therefore, detailed descriptions of the same elements will be omitted. 
     Referring to  FIGS. 2 and 3B , when viewed in the third direction DR 3 , each of the first branch portions BR 1 - 1  may protrude from a first support bar SR 1  to a direction that is substantially parallel to the first direction DR 1 . Each of the second branch portions BR 2 - 1  may protrude from a second support bar SR 2  (refer to  FIG. 1 ) to the direction that is substantially parallel to the first direction DR 1 . The first branch portions BR 1 - 1  may be substantially parallel to the second branch portions BR 2 - 1 . When viewed in the third direction DR 3 , the first branch portions BR 1 - 1  may not overlap the second branch portions BR 2 - 1 . 
     When viewed in the third direction DR 3 , each of the third branch portions BR 3 - 1  may protrude from a third support bar SR 3  to the direction that is substantially parallel to the first direction DR 1 . Each of the fourth branch portions BR 4  may protrude from a fourth support bar SR 4  (refer to  FIG. 1 ) to the direction that is substantially parallel to the first direction DR 1 . The third branch portions BR 3 - 1  may be substantially parallel to the fourth branch portions BR 4 - 1 . 
     When viewed in the third direction DR 3 , the third branch portions BR 3 - 1  may not overlap the fourth branch portions BR 4 - 1 . 
     A first controller CT 1  may move one second branch portion BR 2 - 1  (hereinafter, referred to as a second branch portion BR 2 - 1 ) among the second branch portions BR 2 - 1  in a direction that is substantially parallel to the second direction DR 2 . The first controller CT 1  may control a distance in the direction that is substantially parallel to the second direction DR 2  between one first branch portion BR 1 - 1  (hereinafter, referred to as a first branch portion BR 1 - 1 ), which may be adjacent to the second branch portion BR 2 - 1 , among the first branch portions BR 1 - 1  and the second branch portion BR 2 - 1 . When viewed in the third direction DR 3 , the distance in the direction that is substantially parallel to the second direction DR 2  between the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1  may be adjusted to a first distance BWa- 1  (S 300 ). The first distance BWa- 1  may be greater than the width RW in the direction that may be substantially parallel to the second direction DR 2  of the robot arm RA. 
     When the robot arm RA loads the substrate GL, the robot arm RA may be spaced apart from the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1 . When viewed in the third direction DR 3 , the robot arm RA may easily insert the substrate GL into between the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1 . Accordingly, the reliability of the substrate processing method may be improved. 
     When viewed in the third direction DR 3 , a second controller CT 2  may move one fourth branch portion BR 4 - 1  (hereinafter, referred to as a fourth branch portion BR 4 -_ 1 ) among the fourth branch portions BR 4 - 1  in the direction that is substantially parallel to the second direction DR 2 . The second controller CT 2  may control a distance in the direction that is substantially parallel to the second direction DR 2  between one third branch portion BR 3 - 1  (hereinafter, referred to as a third branch portion BR 3 - 1 ), which may be adjacent to the fourth branch portion BR 4 - 1  among the third branch portions BR 3 - 1  and the fourth branch portion BR 4 - 1 . The distance in the direction that is substantially parallel to the second direction DR 2  between the third branch portion BR 3 - 1  and the fourth branch portion BR 4 - 1  may be substantially simultaneously controlled to correspond to the distance in the direction that is substantially parallel to the second direction DR 2  between the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1 . 
       FIG. 4  is a side view showing the substrate loading cassette CST according to an embodiment of the present disclosure. 
     Referring to  FIGS. 1 and 4 , the substrate GL may be loaded into the cassette CST. 
     Each of the first supporter SP 1 , the second supporter SP 2 , the third supporter SP 3 , and the fourth supporter SP 4  may be provided in plural. The first supporters SP 1  and the second supporters SP 2  may be sequentially arranged in the direction that is substantially parallel to the third direction DR 3 . The third supporters SP 3  and the fourth supporters SP 4  may be sequentially arranged in the direction that is substantially parallel to the third direction DR 3 . 
     The second branch portion BR 2  may be disposed under the first branch portion BR 1 , and the fourth branch portion BR 4  may be disposed under the third branch portion BR 3 . 
     The first branch portion BR 1  and the third branch portion BR 3  may support a first surface of the substrate GL. The second branch portion BR 2  and the fourth branch portion BR 4  may support a second surface that is opposite to the first surface of the substrate GL in the second direction DR 2 . 
       FIG. 4  shows three first supporters SP 1 , three second supporters SP 2 , three third supporters SP 3 , and three fourth supporters SP 4  as a representative example. However, the number of each of the first supporters SP 1 , the second supporters SP 2 , the third supporters SP 3 , and the fourth supporters SP 4  should not be particularly limited as long as they may support the substrate GL. For example, the number of each of the first supporters SP 1 , the second supporters SP 2 , the third supporters SP 3 , and the fourth supporters SP 4  may be two, and they may support the substrate GL. 
       FIG. 5A  is a plan view showing a substrate loading cassette CST according to an embodiment of the present disclosure. In  FIG. 5A , the same reference numerals denote the same elements in  FIG. 3A . Therefore, detailed descriptions of the same elements will be omitted. 
     Referring to  FIGS. 2 and 5A , a substrate GL may be loaded into the cassette CST. When viewed in the third direction DR 3 , a maximum distance in the direction that is substantially parallel to the second direction DR 2  between a first branch portion BR 1  and a second branch portion BR 2  may be adjusted to a second distance BW 1   b  (S 500 ). The cassette CST in which the distance is adjusted to the second distance BW 1   b  may be referred to as operating in a second state. 
     The second distance BW 1   b  may be greater than a thickness GW of the substrate GL in the direction that is substantially parallel to the second direction DR 2 . The second distance BW 1   b  may be smaller than the width RW of the robot arm RA (refer to  FIG. 3A ) in the direction that is substantially parallel to the second direction DR 2 . 
     The first branch portion BR 1  and the second branch portion BR 2  may be disposed adjacent to the substrate GL. When the reinforcing of the substrate GL is performed (S 600 ), the first branch portion BR 1  and the second branch portion BR 2  may support the substrate GL. The first branch portion BR 1  and the second branch portion BR 2  may prevent the substrate GL from shaking. Accordingly, the reinforcing of the substrate GL (S 600 ) may be easily performed. Therefore, the reliability of the substrate loading cassette CST and the substrate processing method may be improved. 
     When viewed in the third direction DR 3 , a minimum distance in the direction that is substantially parallel to the second direction DR 2  between the first branch portion BR 1  and the second branch portion BR 2  may be a second minimum distance BW 2   b . The second minimum distance BW 2   b  may be smaller than the thickness GW of the substrate GL. 
     A distance between the first branch portion BR 1  and the second branch portion BR 2  may increase going from the first frame FR 1  to the second frame FR 2 . The substrate GL loaded into the cassette CST may be supported by the first branch portion BR 1  and the second branch portion BR 2 . The first branch portion BR 1  and the second branch portion BR 2  may prevent the substrate GL from shaking. Accordingly, the reinforcing of the substrate GL may be easily performed (S 500 ). Therefore, the reliability of the substrate loading cassette CST and the substrate processing method may be improved. 
     The first distance BW 1   a  (refer to  FIG. 3A ) may be greater than the second distance BW 1   b . The distance between the first branch portion BR 1  and the second branch portion BR 2  may be adjusted to the first distance BW 1   a  (refer to  FIG. 3A ) (S 300 ) before the loading of the substrate GL (S 400 ). A space to load the substrate GL that is fixed to the robot arm RA (refer to  FIG. 3A ) may be secured in the cassette CST. The first distance BW 1   a  (refer to  FIG. 3A ) between the first branch portion BR 1  and the second branch portion BR 2  may be controlled by taking into account the size of the robot arm. The robot arm RA (refer to  FIG. 3A ) may be prevented from colliding or interfering with the first branch portion BR 1  and the second branch portion BR 2  while the robot arm RA (refer to  FIG. 3A ) loads the substrate GL. Accordingly, the reliability of the automated process of the substrate processing method may be improved. Accordingly, the reliability of the automated process using the robot arm RA (refer to  FIG. 3A ) may be improved, and the damage on the substrate GL caused when loading the substrate GL may be reduced. 
     After the substrate GL is loaded into the cassette CST (S 400 ), the distance between the first branch portion BR 1  and the second branch portion BR 2  may be adjusted to the second distance BW 1   b  (S 500 ). The cassette CST may support the substrate GL using the first branch portion BR 1  and the second branch portion BR 2 , which have the second distance BW 1   b  smaller than the first distance BW 1   a  (refer to  FIG. 3A ). Accordingly, the substrate GL may be prevented from shaking in the reinforcing of the substrate GL (S 600 ). The damage on the substrate GL may be prevented from occurring. Accordingly, the reliability of the substrate loading cassette CST and the substrate processing method may be improved. 
       FIG. 5B  is a plan view showing a substrate loading cassette CST- 1  according to an embodiment of the present disclosure. In  FIG. 5B , the same reference numerals denote the same elements in  FIGS. 3B and 5A . Therefore, detailed descriptions of the same elements will be omitted. 
     Referring to  FIGS. 2 and 5B , when viewed in the third direction DR 3 , a distance between a first branch portion BR 1 - 1  and a second branch portion BR 2 - 1  in the direction that is substantially parallel to the second direction DR 2  may be adjusted to a second distance BWb- 1  (S 500 ). 
     The second distance BWb- 1  may be greater than a thickness GW of a substrate GL in the direction that is substantially parallel to the second direction DR 2 . The second distance BWb- 1  may be smaller than the width RW of the robot arm RA (refer to  FIG. 3B ) in the direction that is substantially parallel to the second direction DR 2 . 
     The first branch portion BR 1 - 1  and the second branch portion BR 2 - 1  may be disposed adjacent to the substrate GL. When the reinforcing of the substrate GL is performed (S 600 ), the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1  may support the substrate GL. The first branch portion BR 1 - 1  and the second branch portion BR 2 - 1  may prevent the substrate GL from shaking. Accordingly, the reinforcing of the substrate GL (S 600 ) may be easily performed. Therefore, the reliability of the substrate loading cassette CST and the substrate processing method may be improved. 
     The first distance BWa- 1  (refer to  FIG. 3B ) may be greater than the second distance BWb- 1 . In the cassette CST- 1 , the distance between the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1  may be adjusted to the first distance BWa- 1  (refer to  FIG. 3B ) (S 300 ) before the loading of the substrate GL (S 400 ). A space to load the substrate GL that is fixed to the robot arm RA (refer to  FIG. 3B ) may be secured in the cassette CST- 1 . Accordingly, the reliability of the automated process using the robot arm RA (refer to  FIG. 3B ) may be improved, and the damage on the substrate GL caused when loading the substrate GL may be reduced. 
     After the loading of the substrate GL into the cassette CST- 1  (S 400 ), the distance between the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1  may be adjusted to the second distance BWb- 1  (S 500 ). The cassette CST- 1  may support the substrate GL using the first branch portion BR 1 - 1  and the second branch portion BR 2 - 1 , which have the second distance BWb- 1  smaller than the first distance BWa- 1  (refer to  FIG. 3B ). Accordingly, the substrate GL may be prevented from shaking in the reinforcing of the substrate GL (S 600 ). Additionally, or alternatively, the damage on the substrate GL may be prevented. Therefore, the reliability of the substrate loading cassette CST- 1  and the substrate processing method may be improved. 
       FIG. 6  is a flowchart showing the process of reinforcing the substrate according to an embodiment of the present disclosure.  FIG. 7  is a view showing a process of chemically reinforcing a substrate according to an embodiment of the present disclosure. 
     Referring to  FIGS. 6 and 7 , the reinforcing of the substrate (S 600 ) may include preheating the cassette CST and the substrate GL (S 610 ), chemically reinforcing the cassette CST and the substrate GL (S 620 ), cooling the cassette CST and the substrate GL (S 630 ), and cleaning the cassette CST and the substrate GL (S 640 ). 
     The preheating of the cassette CST and the substrate GL (S 610 ) may be a process of preheating and heating the substrate GL at a certain level of temperature to chemically reinforce the substrate GL. The preheating of the substrate GL (S 610 ) may be performed by repeating the process of increasing temperature and maintaining a constant temperature. Therefore, the substrate GL may be prevented from being damaged due to a thermal expansion caused by a sudden heating of the substrate GL. The preheating (S 610 ) may improve reactivity in the chemical reinforcing of the cassette CST and the substrate GL (S 620 ). 
     In the chemical reinforcing of the cassette CST and the substrate GL (S 620 ), the cassette CST and the substrate GL may be loaded into the reinforcing furnace CB. The reinforcing furnace CB may accommodate a melting solution MS used for the chemical reinforcing process. The substrate GL may be chemically reinforced by carrying out an ion substitution reaction with the melting solution MS. For example, the melting solution MS may include a potassium nitrate solution. 
     The reinforcing furnace CB may have chemical and heat resistance. For example, the reinforcing furnace CB may include stainless steel. The reinforcing furnace CB may uniformly maintain a temperature of the melting solution MS and may prevent heat loss. 
     The substrate GL may be preheated in the preheating (S 610 ). Therefore, the ion substitution reaction may be easily performed between a sodium ion on a surface of the substrate GL and the potassium nitrate solution that is the melting solution MS. 
     The ion substitution reaction may be performed in the substrate GL provided in the melting solution MS with high temperature. For example, the high temperature may be within a range from about 400° C. to about 500° C. In the chemical reinforcing of the cassette CST and the substrate GL (S 620 ), small particles on the substrate GL may be ion-exchanged with large particles of melting solution MS. For example, the small particles may be sodium ions, and the large particles may be potassium ions. The melting solution MS may include liquefied potassium nitrate (KNO 3 ). The sodium ions (Na + ) with a small ionic radius, which are distributed on the surface of the substrate GL, may be substituted with the potassium ions (K + ) with a large ionic radius of the potassium nitrate solution. A compressive stress layer may be formed on the surface of the substrate GL by the ion substitution reaction. Therefore, a surface density may be improved. 
     The cooling of the cassette CST and the substrate GL (S 630 ) may slowly cool the substrate GL. The cooling of the substrate GL (S 630 ) may prevent the substrate GL that is ion-substituted from being deformed and may remove residual stress. 
     The cooling of the cassette CST and the substrate GL (S 630 ) may prevent damaging impacts on the substrate GL that may occur when a portion of the surface of the ion-substituted substrate GL, which may be unstable and in high temperature, is combined with the potassium nitrate and solidifies. Additionally or alternatively, in a case where the cassette CST and the substrate GL are quickly cooled down, impacts occurring inside the substrate GL due to different cooling rates depending on portions of the substrate GL may be prevented. Therefore, internal cracks may be prevented from occurring in the substrate GL. 
     The cleaning of the cassette CST and the substrate GL (S 640 ) may bubble-clean the substrate GL using air bubbles. The substrate GL may be cleaned and substantially simultaneously cooled through the cleaning of the cassette CST and the substrate GL (S 640 ). Accordingly, the residual stress generated in the substrate GL in the chemical reinforcing (S 620 ) may be removed, and as a result, the substrate GL may be further stabilized. 
     Although the embodiments of the present disclosure have been described, it is understood that the present disclosure should not be limited to these embodiments but various changes and modifications can be made by one ordinary skilled in the art within the spirit and scope of the present disclosure as hereinafter claimed. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, and the scope of the present inventive concept shall be determined according to the attached claims.