Abstract:
Exemplary embodiments of the inventive concept provide a plasma treatment apparatus with a substrate support unit, a plasma unit, a first rotation driving unit, and a gas supply part. The substrate support unit supports a substrate. The plasma unit generates a plasma and provides the plasma to the substrate. The first rotation driving unit is coupled to the plasma unit to rotate the plasma unit with respect to the substrate support unit. The gas supply part supplies a source gas to the plasma unit. The plasma unit includes a body, a first electrode located in the body, a second electrode located in the body and facing the first electrode, and a pipe located between the first and second electrodes to flow the source gas therethrough.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0106065, filed on Jul. 27, 2015, the content of which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    The present disclosure relates to a plasma treatment apparatus and methods of plasma treating a substrate using the same. 
         [0004]    2. Description of the Related Art 
         [0005]    A plasma treatment apparatus may perform various treatment processes on a substrate using plasma. For instance, a plasma treatment apparatus may perform a surface treatment process on a substrate. The surface treatment process may modify a surface of the substrate and a surface energy of the surface increases due to the surface treatment process. 
         [0006]    The surface treatment process may be applied as part of a process used to form coating layers on the substrate. For example, when the surface treatment process is performed on a first coating layer after the first coating layer is formed on the substrate, an adhesive strength between the first coating layer and a second coating layer formed on the first coating layer may be improved. 
         [0007]    A mobile display device (e.g., a smart phone) may include a window covering a display screen. The window may be formed of a plastic material, and coating layers may be formed on the window to improve the hardness of the window. In addition, a surface treatment process may be applied when the coating layers are formed on the window, and thus the adhesive strength between the coating layers may be improved. 
       SUMMARY 
       [0008]    Aspects of example embodiments of the present disclosure provide a plasma treatment apparatus capable of easily performing a plasma treatment process on a variety of substrates. 
         [0009]    The present disclosure provides methods of plasma treating the substrate using the plasma treatment apparatus. 
         [0010]    Embodiments of the inventive concept provide a plasma treatment apparatus including a substrate support unit, a plasma unit, a first rotation driving unit, and a gas supply part. 
         [0011]    In some embodiments, the substrate support unit supports a substrate. The plasma unit generates a plasma and provides the plasma to the substrate. The first rotation driving unit is coupled to the plasma unit to rotate the plasma unit with respect to the substrate support unit. The gas supply part supplies a source gas to the plasma unit. 
         [0012]    In some embodiments, the plasma unit may include a body, a first electrode located in the body, a second electrode located in the body and facing the first electrode, and a pipe (e.g., a tube) located between the first and second electrodes to flow the source gas therethrough. 
         [0013]    In some embodiments, the first rotation driving unit may include a first rotation axis and a first rotation driving part. The outlet of the plasma unit may rotate in a clockwise direction or a counter-clockwise direction by the first rotation driving unit when viewed in a side view (e.g., relative to the first rotation axis). 
         [0014]    In some embodiments, the plasma treatment apparatus may further include a second rotation driving unit. The second rotation driving unit may be coupled to the plasma unit to rotate the plasma unit in a clockwise direction or a counter-clockwise direction by the first rotation driving unit when viewed in a plan view (e.g., relative to the first rotation axis). 
         [0015]    In some embodiments, the plasma treatment apparatus may further include a third rotation driving unit. The third rotation driving unit may be coupled to the plasma unit to change a direction to which the outlet of the plasma unit faces to a lower end portion of the chamber from an upper end portion of the chamber. 
         [0016]    Embodiments of the inventive concept provide a method of plasma treating a substrate as follows. The substrate is located in a chamber. A plasma unit generating a plasma rotates with respect to the substrate and the substrate rotates with respect to the plasma unit. 
         [0017]    According to some embodiments, at least one of the plasma unit and the substrate rotates to allow an outlet of the plasma unit to face a bending portion of the substrate (e.g., a curved surface portion). 
         [0018]    According to some embodiments, the plasma units rotate in the reactive space of the chamber by the rotation driving units. Thereby, the outlets of the plasma units may be controlled to face various directions, and as a result, the plasma discharged through the outlets may be isotropically supplied to the substrate. 
         [0019]    As a result, a surface treatment process may be uniformly performed on an entire surface of the substrate by using the plasma units. In addition, the surface treatment process may be easily performed on the bending portion of the substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The above and other features of the present disclosure will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
           [0021]      FIG. 1  is a side view showing a plasma treatment apparatus according to some exemplary embodiments of the present disclosure; 
           [0022]      FIG. 2A  is a cross-sectional view showing a first plasma unit, the cross section being taken along the line I-I′ shown in  FIG. 1 ; 
           [0023]      FIG. 2B  is a plan view showing plasma units according to  FIG. 1 ; 
           [0024]      FIGS. 3A and 3B  are side views showing plasma units rotated by a first rotation driving unit according to some embodiments; 
           [0025]      FIG. 3C  is a plan view showing plasma units rotated by a second rotation driving unit according to some embodiments; 
           [0026]      FIG. 3D  is a side view showing plasma units rotated by a third rotation driving unit according to some embodiments; 
           [0027]      FIG. 4  is a side view showing a plasma treatment apparatus according to some exemplary embodiments of the present disclosure; and 
           [0028]      FIGS. 5A to 5C  are views showing methods of plasma treating a substrate according to some embodiments using the plasma treatment apparatus shown in  FIG. 1  when a plurality of coating layers is formed on the substrate. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Hereinafter, exemplary embodiments of the present invention will be described with reference to accompanying drawings. In the following description, the same reference numerals will be assigned to elements and structures having substantially the same function or configuration and detailed descriptions thereof will be omitted in order to avoid redundancy. 
         [0030]    In the drawings, the thickness of layers, films, and regions may be exaggerated for clarity. 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, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. 
         [0031]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms “a” and “an” 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 “including,” when used in this specification, specify the presence of the 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. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. 
         [0032]    Spatially relative terms, such as “beneath,” “below,” “lower,” “under,” “above,” “upper,” and the like, may be used herein for ease of explanation to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or in operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the example terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly. 
         [0033]    As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. Further, the use of “may” when describing embodiments of the present invention refers to “one or more embodiments of the present invention.” As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively. Also, the term “exemplary” is intended to refer to an example or illustration. 
         [0034]    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 the present invention 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/or the present specification, and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein. 
         [0035]      FIG. 1  is a side view showing a plasma treatment apparatus  500  according to some exemplary embodiments of the present disclosure.  FIG. 2A  is a cross-sectional view showing a first plasma unit  200 , the cross section being taken along the line I-I′ shown in  FIG. 1 , and  FIG. 2B  is a plan view showing plasma units  200  and  201  shown in  FIG. 1 . 
         [0036]    Referring to  FIGS. 1, 2A, and 2B , the plasma treatment apparatus  500  may perform a plasma treatment on each of substrates W 1 , W 2 , W 3 , W 4 , W 5 , and W 6 . In some exemplary embodiments, each of the substrates W 1  to W 6  may bebut is not limited to, a window covering a display part of a display device, and each of the substrates W 1  to W 6  may include a bending portion BP having a curved surface. 
         [0037]    In some exemplary embodiments, the plasma treatment apparatus  500  may include a chamber CB, substrate support units  51 ,  52 ,  53 ,  54 ,  55 , and  56 , gas supply parts  100  and  101 , plasma units  200  and  201 , first rotation driving units  80  and  85 , a second rotation driving unit  400 , and a third rotation driving unit  300 . 
         [0038]    The chamber CB may include an upper end portion P 3 , a lower end portion P 4 , and a plurality of sidewalls connecting the upper end portion P 3  and the lower end portion P 4 . For example,  FIG. 1  shows a first sidewall P 1  and a second sidewall P 2  facing the first sidewall P 1 , but the chamber CB is not limited thereto or thereby. The chamber CB is provided with a reactive space RS defined therein, in which the plasma treatment is performed on the substrates W 1  to W 6 . 
         [0039]    In some exemplary embodiments, the reactive space RS may be maintained in a vacuum state. In such embodiments, the plasma treatment apparatus  500  may further include a vacuum pump (not shown) connected to the reactive space RS. 
         [0040]    However, the reactive space RS should be understood as not limited to being maintained in a vacuum state. That is, the reactive space RS may be maintained in an atmospheric-pressure state according to some embodiments. 
         [0041]    In some exemplary embodiments, a substrate entrance D 1  and a substrate exit D 2  are each adjacent the upper end portion P 3  and the lower end portion P 4  of the chamber CB. The substrate entrance D 1  extends through the first sidewall P 1  and the substrate exit D 2  extends through the second sidewall D 2 . 
         [0042]    The plasma treatment apparatus  500  may further include a transfer rail TR to transfer the substrates W 1  to W 6 . The transfer rail TR crosses the reactive space RS with one end of the transfer rail TR outside of substrate entrance D 1  of the chamber CB, and the other end of the transfer rail TR outside of substrate exit D 1  of the chamber CB. In some embodiments, the substrates W 1  to W 6  enter into the reactive space RS through the substrate entrance D 1  and exit outside of the chamber CB through the substrate exit D 2 . 
         [0043]    The substrate support units  51  to  56  (e.g., substrate supports) support the substrates W 1  to W 6 , respectively, and rotate the substrates W 1  to W 6  in the reactive space RS, as further described below. 
         [0044]    In some embodiments, the substrate support units  51  to  53  are adjacent to the upper end portion P 3  of the chamber CB and the substrate support units  54  to  56  are adjacent to the lower end portion P 4  of the chamber CB. Because the substrate support units  51  to  56  may have substantially the same structure and function, a first substrate support unit  51  (of the substrate support units  51  to  56 ) will be described in detail as a representative example, and a first substrate W 1  (of the substrates W 1  to W 6  will be described in detail as a representative example. The first substrate W 1  is coupled to the first substrate support unit  51  (for example, see  FIG. 1 ). 
         [0045]    In some embodiments, the first substrate support unit  51  may include a driving part RD, a rotation axis RA, and a holding part RC (for example, see  FIG. 1 ). The driving part RD includes a motor to generate a rotational force and the rotation axis RA (e.g., a rotation shaft having the rotation axis RA) is connected to the driving part RD to receive the rotational force from the driving part RD. One end of the holding part RC is connected to the rotation axis RA and the other end of the holding part RC holds the first substrate W 1 . 
         [0046]    In some exemplary embodiments, the holding part RC may include a chuck (not shown) to hold the first substrate W 1  and the chuck may include a support pin (not shown) making contact with the first substrate W 1 . 
         [0047]    When a rotational force is generated by the driving part RD, the rotational force is applied to the rotation axis RA, and the holding part RC rotates in a first clockwise direction RDR 1  or a first counter-clockwise direction RDR 1 - 1  in the reactive space RS when viewed from a side surface (i.e., rotates about rotation axis RA, for example, see  FIG. 1 ). The first substrate W 1  is interlocked with the rotation of the holding part RC and rotates in the first clockwise direction RDR 1  or the first counter-clockwise direction RDR 1 - 1  in the reactive space RS (e.g., depending on the rotation of the holding part RC). 
         [0048]    In some embodiments where the first substrate W 1  rotates in the reactive space RS (i.e., rotating about rotation axis RA), an upper surface of the first substrate W 1 , a lower surface of the first substrate W 1 , and the curved surface of the bending portion BP may be oriented toward the plasma units  200  and  201 . The plasma generated by the plasma units  200  and  201  (e.g., plasma generators) may be uniformly applied to the entire surface of the first substrate W 1 , and as a result, a surface treatment process may be uniformly performed on the entire surface of the first substrate W 1  by the plasma provided from the plasma units  200  and  201 . 
         [0049]    In some embodiments, the gas supply parts  100  and  101  (e.g., gas suppliers) may provide the plasma units  200  and  201  with a source gas SG. The gas supply parts  100  and  101  include a first gas supply part  100  and a second gas supply part  101  and the plasma units  200  and  201  include a first plasma unit  200  and a second plasma unit  201 . 
         [0000]    The first gas supply part  100  provides the source gas SG to the first plasma unit  200  through a first gas line PR 1  and the second gas supply part  101  provides the source gas SG to the second plasma unit  201  through a second gas line PR 2 . 
         [0050]    In some exemplary embodiments, the source gas SG may include at least one of: an argon gas, a hydrogen gas, a nitrogen gas, and an oxygen gas. 
         [0051]    The first and second gas lines PR 1  and PR 2  may have a flexible shape. For instance, the first and second gas lines PR 1  and PR 2  may be a hose formed of a plastic material. Accordingly, when the first and second plasma units  200  and  201  rotate, the first and second gas lines PR 1  and PR 2  may be flexible. As a result, the source gas SG may be stably provided to the first and second plasma units  200  and  201  through the first and second gas lines PR 1  and PR 2 . In some embodiments, the first and second plasma units  200  and  201  receive the source gas SG from the first and second gas supply parts  100  and  101  and generate the plasma PS. The first plasma unit  200  may include a first outlet DH 1  through which the plasma PS is discharged (for example, the first plasma unit  200  and/or the first outlet DH 1  may be located in the reactive space RS) and the second plasma unit  201  may include a second outlet DH 2  through which the plasma PS is discharged (for example, the second plasma unit  201  and/or the second outlet DH 2  may be located in the reactive space RS). Therefore, when the first and second plasma units  200  and  201  are operated, the reactive space RS is filled with the plasma PS. The first and second plasma units  200  and  201  may have substantially the same structure and function, and thus the first plasma unit  200  will be described in detail as a representative example. 
         [0052]    The first plasma unit  200  may include a body BD, a first electrode E 1 , a second electrode E 2 , and a pipe FP (for example, see  FIG. 2A ). The first outlet DH 1  is located at one end of the body BD. The first and second electrodes E 1  and E 2  are located in the body BD and face each other such that the pipe FP (e.g., a tube) is located between the first and second electrodes E 1  and E 2 . 
         [0053]    In some embodiments, the first and second electrodes E 1  and E 2  may be connected to a direct-current power source, forming an electric field EF between the first and second electrodes E 1  and E 2 . When the source gas SG is provided through the pipe FP while the electric field EF is formed, the source gas SG is converted to an ionic state by electrons provided from one of the first and second electrodes E 1  and E 2 , such that the plasma PS is generated. In addition, the generated plasma PS is discharged through the first outlet DH 1 . 
         [0054]    In some embodiments, the first rotation driving units  80  and  85  may be coupled to the plasma units  200  and  201 , respectively (e.g., in a one-to-one correspondence). Because the first rotation driving units  80  and  85  may have substantially the same structure and function, hereinafter, only one first rotation driving unit  80  will be described in detail with reference to  FIGS. 3A and 3B  as a representative example. 
         [0055]      FIGS. 3A and 3B  are side views showing the plasma units  200  and  201  rotated by the first rotation driving unit  80  according to some embodiments. 
         [0056]    Referring to  FIGS. 1, 3A, and 3B , the first rotation driving unit  80  (e.g., first rotation driver) may include a first rotation driving part  81  and a first rotation axis  82 . The first rotation driving part  81  may include a motor to generate a rotational force and the first rotation axis  82  may be connected to the first rotation driving part  81  to receive the rotational force from the first rotation driving part  81 . 
         [0057]    The first rotation axis  82  may be coupled to the first plasma unit  200 . Accordingly, when the first rotation driving part  81  is operated to rotate the first rotation axis  82 , the first plasma unit  200  rotates by the rotation of the first rotation axis  82 . Specifically, the first outlet DH 1  of the first plasma unit  200  rotates in the first clockwise direction RDR 1  or the first counter-clockwise direction RDR 1 - 1  when viewed in a side surface (for example, see  FIGS. 3A and 3B ). As a result, the plasma PS discharged through the first outlet DH 1  may be uniformly provided to the entire surface of each of the substrates W 1 , W 2 , and W 3 . 
         [0058]    The second rotation driving unit  400  (e.g., second rotation driver) may be coupled to the first and second plasma units  200  and  201 . Hereinafter, the structure and function of the second rotation driving unit  400  will be described in detail with reference to  FIG. 3C . 
         [0059]      FIG. 3C  is a plan view showing plasma units rotated by the second rotation driving unit  400  according to some embodiments. 
         [0060]    Referring to  FIGS. 1 and 3C , the second rotation driving unit  400  may include a second rotation driving part  401 , a second rotation axis  405 , and a support part  403 . 
         [0061]    The second rotation driving part  401  may include a motor to generate a rotational force. The second rotation axis  405  may be coupled to the second rotation driving part  401  to receive the rotational force. The support part  403  may be coupled to the second rotation axis  405  and rotates in a second clockwise direction RDR 2  or a second counter-clockwise direction RDR 2 - 1  by the rotational force when viewed in a plan view (for example, see  FIG. 3C ). 
         [0062]    In some exemplary embodiments, the support part  403  may have a substantially circular plate shape, but is not limited thereto or thereby. In some embodiments, for instance, the support part  403  may have a frame shape connecting the first and second plasma units  200  and  201 . 
         [0063]    The support part  403  may be coupled to the first rotation driving units  80  and  85 , the first plasma unit  200 , and the second plasma unit  201 . Thus, in some embodiments where the support part  403  rotates in the second clockwise direction RDR 2  or the second counter-clockwise direction RDR 2 - 1  in accordance with the driving of the second rotation driving unit  400  (for example, see  FIG. 3C ), the first and second plasma units  200  and  201  rotate in the second clockwise direction RDR 2  or the second counter-clockwise direction RDR 2 - 1  when viewed in the plan view (i.e., based on the rotation of the second rotation driving unit  400 ). 
         [0064]    In addition, in some embodiments where the first rotation driving units  80  and  85  and the second rotation driving unit  400  are substantially simultaneously driven, the first and second plasma units  200  and  201  rotate not only in the first clockwise direction RDR 1  and the first counter-clockwise direction RDR 1 - 1  but also in the second clockwise direction RDR 2  or the second counter-clockwise direction RDR 2 - 1 . Accordingly, the first and second outlets DH 1  and DH 2  of the first and second plasma units  200  and  201  may be controlled to face various directions, and as a result, the plasma PS discharged through the first and second outlets DH 1  and DH 2  may be isotropically supplied to the substrates W 1 , W 2 , and W 3 . 
         [0065]    A third rotation driving unit  300  (e.g., third rotation driver) may be coupled to the first and second plasma units  200  and  201 . Hereinafter, the structure and function of the third rotation driving unit  300  will be described in detail with reference to  FIG. 3D . 
         [0066]      FIG. 3D  is a side view showing plasma units rotated by the third rotation driving unit  300  according to some embodiments. 
         [0067]    Referring to  FIGS. 1 and 3D , the third rotation driving unit  300  may include a third rotation driving part  301  and a third rotation axis  305 . 
         [0068]    The third rotation driving part  301  may include a motor to generate a rotational force. One end of the third rotation axis  305  may be coupled to the third rotation driving part  301  and the other end of the third rotation axis  305  may be fixed to the support part  403 . As a result, the rotational force generated by the third rotation driving part  301  may be applied to the support part  403  through the third rotation axis  305 , and thus the support part  403  may rotate by the rotational force. 
         [0069]    In addition, in some embodiments, the orientation of the support part  403  relative to the third rotation axis  305  may be reversed by the rotation of the third rotation driving part  301 . As a result, the orientation of the first and second plasma units  200  and  201  (located on the support part  403 ) relative to the third rotation axis  305  may be reversed. Accordingly, the direction to which the first and second outlets DH 1  and DH 2  face may be changed from the upper end portion P 3  of the chamber CB to the lower end portion P 4  of the chamber CB. 
         [0070]    As shown in  FIG. 1 , in some embodiments where the first and second plasma units  200  and  201  face the upper end portion P 3  of the chamber CB, the substrates W 1  to W 3  (adjacent to the upper end portion P 3 ) may be plasma treated. In addition, as shown in  FIG. 3D , in some embodiments where the first and second plasma units  200  and  201  face the lower end portion P 4  of the chamber CB, the substrates W 4  to W 6  (adjacent to the lower end portion P 4 ) may be plasma treated. 
         [0071]    In some embodiments, the direction to which the first and second outlets DH 1  and DH 2  face (e.g., upper end portion P 3  or lower end portion P 4 ) may be controlled by using the third rotation driving unit  300  (e.g., to rotate third rotation axis  305 ). As a result, the plasma treatment process may be substantially simultaneously performed on the substrates W 1  to W 6  located at the upper and lower end portions P 3  and P 4  of the chamber CB. 
         [0072]      FIG. 4  is a side view showing a plasma treatment apparatus  501  according to some exemplary embodiments of the present disclosure. In  FIG. 4 , the same reference numerals denote the same elements in the above-mentioned embodiments, and thus detailed descriptions of the same elements will be omitted. 
         [0073]    Referring to  FIG. 4 , the plasma treatment apparatus  501  may include a chamber CB, substrate support units  51  to  56 , gas supply parts  100 ,  101 ,  102 , and  103 , plasma units  200 ,  201 ,  202 , and  203 , first rotation driving units  80 ,  85 ,  86 , and  87 , and a second rotation driving unit  400 . 
         [0074]    In some exemplary embodiments, the plasma units  200  to  203  are located at upper and lower end portions of the support part  403 . Specifically, the first and second plasma units  200  and  201  may be located at the upper end portion of the support part  403  and the third and fourth plasma units  202  and  203  may be located at the lower end portion of the support part  403 . 
         [0075]    In some embodiments, the gas supply parts  100  to  103  correspond to the plasma units  200  to  203 , respectively, and supply the source gas to the plasma units  200  to  203 . The gas supply units  100  to  103  may include first, second, third, and fourth gas lines PR 1 , PR 2 , PR 3 , and PR 4  and the first to fourth gas lines PR 1  to PR 4  may be connected to the plasma units  200  to  203 , respectively (e.g., in a one-to-one correspondence). 
         [0076]    The first rotation driving units  80 ,  85 ,  86 , and  87  may be coupled to the plasma units  200  to  203 , respectively (e.g. in a one-to-one correspondence), to rotate the plasma units  200  to  203  in a first clockwise direction RDR 1  and a first counter-clockwise direction RDR 1 - 1  when viewed in the side view (for example, see  FIG. 4 ). 
         [0077]    In some embodiments, the second rotation driving unit  400  may be coupled to the plasma units  200  to  203  to rotate the plasma units  200  to  203  in a second clockwise direction RDR 2  and a second counter-clockwise direction RDR 2 - 1  when viewed in the side view (for example, see  FIG. 2B ). 
         [0000]    In the reactive space RS, a space corresponding to an upper portion of the support part  403  will be referred to herein as an upper reactive space and a space corresponding to a lower portion of the support part  403  will be referred to herein as a lower reactive space. When the first rotation driving units  80 ,  85 ,  86 , and  87  and the second rotation driving unit  400  are driven, the direction in which each of first and second outlets DH 1  and DH 2  of the first and second plasma units  200  and  201  faces may be randomly determined in the upper reactive space, and the direction in which each of third and fourth outlets DH 3  and DH 4  of the third and fourth plasma units  202  and  203  faces may be randomly determined in the lower reactive space. 
         [0078]    Accordingly, the plasma discharged through the first and second outlets DH 1  and DH 2  may be isotropically supplied to substrates W 1 , W 2 , and W 3  adjacent to the upper end portion P 3 , and the plasma discharged through the third and fourth outlets DH 3  and DH 4  may be isotropically supplied to substrates W 4 , W 5 , and W 6  adjacent to the lower end portion P 4 . 
         [0079]      FIGS. 5A to 5C  are views showing a method of plasma treating the substrate W 1  using the plasma treatment apparatus shown in  FIG. 1  when a plurality of coating layers HC is formed on the substrate W 1 , according to some embodiments. 
         [0080]    Referring to  FIG. 5A , a spray unit NZ may provide a first coating solution CS 1  to the substrate W 1  to form a first coating layer L 1  on the substrate W 1 . In some exemplary embodiments, the substrate W 1  may be, but is not limited to, a window covering a display screen of a display device and the substrate W 1  may include a bending portion BP to cover a curved surface of the display screen. 
         [0081]    The first coating solution CS 1  may include an organic material, an inorganic material, or a hybrid material obtained by mixing an organic material and an inorganic material. For instance, the organic material may include an acryl-based compound and an epoxy-based compound and the inorganic material may include silica and aluminum. 
         [0082]    Referring to  FIG. 5B , the plasma treatment process may be performed on the substrate W 1  (on which the first coating layer L 1  is formed) using the plasma treatment apparatus  500  described with reference to  FIG. 1 . For example, in more detail, the plasma units  200  and  201  of the plasma treatment apparatus may be driven to generate the plasma PS and the plasma PS may be supplied to an exposed surface of the first coating layer L 1 . Accordingly, the plasma treatment process may be performed on the exposed surface of the first coating layer L 1  by the plasma PS. 
         [0083]    In some exemplary embodiments, as described with reference to  FIGS. 1, 3A, and 3B , the plasma units  200  and  201  may rotate when the plasma treatment process is performed. Specifically, when the first rotation driving units  80  and  81  are driven, the plasma units  200  and  201  rotate in the first clockwise direction RDR 1  and the first counter-clockwise direction RDR 1 - 1  (for example, see  FIG. 1 ). 
         [0084]    In addition, when the plasma treatment process is performed, the second rotation driving unit  400  may be driven to rotate the plasma units  200  and  201  in the second clockwise direction RDR 2  and the second counter-clockwise direction RDR 2 - 1  when viewed in a plan view as described with reference to  FIGS. 1 and 3C . 
         [0085]    Further, when the plasma treatment process is performed, the substrate W 1  may rotate as described with reference to  FIG. 1 . More particularly, the substrate W 1  may rotate in the first clockwise direction RDR 1  and the first counter-clockwise direction RDR 1 - 1  by the substrate support unit  51  (for example, see  FIG. 1 ). 
         [0086]    Therefore, the plasma PS discharged from the plasma units  200  and  201  may be isotropically supplied to the substrate W 1  by the driving of the first and second rotation driving units. As a result, the flat portion of the window W 1  and the surface of the first coating layer L 1  formed on the bending portion BP may be uniformly plasma treated. 
         [0087]    In some exemplary embodiments, when the plasma treatment process is performed, the plasma units  200  and  201  relative to the third rotation axis  305  may be reversed (e.g., up and down) by the driving of the third rotation driving unit  300  as described with reference to  FIGS. 1 and 3D  (e.g., the orientation of plasma units  200  and  201  can be reversed). In such embodiments, although a plurality of substrates W 1  to W 6  are located at the upper and lower end portions P 3  and P 4  of the chamber CB, the plasma treatment process may be easily performed on the substrates W 1  to W 6  because the orientation of the plasma units  200  and  201  relative to the third rotation axis  305  may be reversed by the third rotation driving unit  300 . 
         [0088]    Referring to  FIG. 5C , after the surface treatment process is completely performed on the first coating layer L 1 , the spray unit NZ may provide a second coating solution CS 2  to the substrate W 1  to form a second coating layer L 2  on the first coating layer L 1 . 
         [0089]    Similar to the first coating solution CS 1 , the second coating solution CS 2  may include an organic material, an inorganic material, or a hybrid material obtained by mixing the organic material and the inorganic material. 
         [0090]    As described with reference to  FIG. 5B , the surface of the first coating layer L 1  may be plasma treated before the second coating layer L 2  is formed. Thus, in some embodiments where the second coating layer L 2  is formed on the first coating layer L 1 , the adhesive strength between the first coating layer L 1  and the second coating layer L 2  may be improved. As a result, although the coating layers HC include the first and second coating layers L 1  and L 2  stacked one on another (for example, see  FIG. 5C ), the first and second coating layers L 1  and L 2  may be prevented from being separated from each other. 
         [0091]    Although the exemplary embodiments of the present invention have been described, it is understood that the present invention should not be limited to these exemplary embodiments but various changes and modifications can be made by one ordinary skilled in the art within the spirit and scope of the present invention as hereinafter claimed.