Patent Publication Number: US-2023133340-A1

Title: Bonding apparatus and bonding method

Description:
This application is a divisional of U.S. patent application Ser. No. 16/573,086, filed on Sep. 17, 2019, which claims priority to Korean patent application 10-2018-0134621, filed on Nov. 5, 2018, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference. 
    
    
     BACKGROUND 
     1. Field 
     The disclosure generally relates to a bonding apparatus and a bonding method. 
     2. Description of Related Art 
     In general, a display device includes a driving circuit connected to a signal line to supply signal. The driving circuit is typically implemented with an integrated circuit (“IC”) chip. The IC chip may include or be configured with a chip-on-film (“COF”) in which a plurality of conductive lead lines are formed on an insulating film such as polyimide. The COF may be referred to as a tape-carrier-package (“TCP”). The COF may be attached onto a display panel assembly through a tape automated bonding (“TAB”) process. The driving circuit attached as described above is electrically connected to a signal line of the display panel assembly through the lead line of the COF. 
     The lead line of the COF may include a plurality of output-side lead lines and a plurality of input-side lead lines, which are respectively connected to an output end and an input end of the IC chip. The signal line of the display panel assembly may include a plurality of connection pads located in the vicinity of an edge of the display panel assembly. The output-side lead line of the COF may be mechanically and electrically connected to the connection pad of the display panel assembly, and the input-side lead line of the COF may be connected a printed circuit board (“PCB”) for transmitting several signals to a driving IC through soldering or the like. An output end of the COF and the connection pad of the display panel assembly may be attached to each other through an anisotropic conductive film (“ACF”). 
     SUMMARY 
     Embodiments provide a bonding apparatus and a bonding method, which simplifies the layout of process facilities through conveyance and rotation in a tape automated bonding (“TAB”) process of a chip-on-film (“COF”). 
     According to an embodiment of the disclosure, a bonding apparatus includes: an anisotropic conductive film (“ACF”) attachment unit which attaches a first ACF and a second ACF onto a display panel assembly; a compression unit which compresses a COF on the first ACF and compresses a second COF on the second ACF; and a buffer unit which rotates the display panel assembly, on which the first ACF and the second COF are compressed. 
     In an embodiment, each of the ACF attachment unit, the compression unit and the buffer unit may include a conveyor which transfers the display panel assembly in a first direction toward the compression unit from the ACF attachment unit and in a second direction toward the ACF attachment unit from the compression unit. 
     In an embodiment, the buffer unit may be disposed prior to the ACF attachment unit, and rotate the display panel assembly transferred from the ACF attachment unit by about 180 degrees and then transfer the rotated display panel assembly to the ACF attachment unit. 
     In an embodiment, the ACF attachment unit may transfer the display panel assembly, to which the first ACF is attached, to the compression unit, and attach the second ACF onto the display panel assembly rotated by the buffer unit. 
     In an embodiment, the compression unit may transfer the display panel assembly, on which the first COF is compressed, to the ACF attachment unit, and transfer the display panel assembly, on which the second COF is compressed, to an outside. 
     In an embodiment, the buffer unit may be disposed prior to the compression unit, and rotate the display panel assembly transferred from the compression unit by about 180 degrees and then retransfer the rotated display panel assembly to the compression unit. 
     In an embodiment, the ACF attachment unit may transfer the display panel assembly, to which the first ACF is attached, to the compression unit, and attach the second ACF to the display panel assembly transferred from the compression unit. 
     In an embodiment, the compression unit may transfer the display panel assembly, on which the first COF and the second COF are compressed, to the buffer unit, and convey the display panel assembly rotated in the buffer unit to the ACF attachment unit. 
     In an embodiment, the bonding apparatus may further include: a first ACF transfer unit disposed at a side of the ACF attachment unit, where the first ACF transfer unit may provide the first ACF; and a second ACF transfer unit disposed at an opposing side of the ACF attachment unit, where the second ACF transfer unit may provide the second ACF. 
     In an embodiment, the bonding apparatus may further include: a first COF transfer unit disposed at a side of the compression unit, where the first COF transfer unit may provide the first COF; and a second COF transfer unit disposed at an opposing side of the compression unit, where the second COF transfer unit may provide the second COF. 
     In an embodiment, a connection pad on the display panel assembly may be aligned adjacent to the first ACF transfer unit, and be aligned adjacent to the second ACF transfer unit when the display panel assembly is rotated by the buffer unit. 
     In an embodiment, the first COF may be electrically connected to a first connection pad on the display panel assembly, and the second COF may be electrically connected to a second connection pad on the display panel assembly. 
     In an embodiment, the first connection pad and the second connection pad may be connected to a first sub-pixel and a second sub-pixel, respectively. 
     In an embodiment, the first COF and the second COF may not be aligned with each other in an extending direction of a gate line. 
     In an embodiment, the compression unit may include: a preliminary compression unit which preliminarily compresses the first COF on the first ACF, and preliminary compresses the second COF on the second ACF; and a primary compression unit which primarily compresses the preliminarily compressed first COF and the preliminarily compressed second COF. 
     According to another embodiment of the disclosure, a bonding method includes: a first TAB process including attaching a first ACF and a first COF onto a display panel assembly while the display panel assembly is transferred in a first direction; a retransferring process including conveying the display panel assembly in a second direction opposite to the first direction, and rotating the display panel assembly on a plane; and a second TAB process including attaching a second ACF and a second COF onto the display panel assembly while the rotated display panel assembly is retransferred in the first direction. 
     In an embodiment, the first TAB process, the retransferring process and the second TAB process may be performed by a bonding apparatus including a conveyor which conveys the display panel assembly in the first direction and the second direction. 
     In an embodiment, the retransferring process may include: retransferring, in the second direction, the display panel assembly transferred in the first direction; rotating the retransferred display panel assembly by about 180 degrees; and transferring the rotated display panel assembly in the first direction. 
     In an embodiment, the retransferring process may include: rotating the display panel assembly transferred in the first direction; and retransferring the display panel assembly in the second direction. 
     According to still another embodiment of the disclosure, a bonding method includes: a first TAB process including attaching a first ACF onto a display panel assembly in an ACF attachment unit, and compressing a first ACF on the first ACF in a compression unit, while the display panel assembly is transferred in a first direction; a retransferring process including retransferring the display panel assembly in a second direction opposite to the first direction, and rotating the display panel assembly on a plane; and a second TAB process including attaching a second ACF onto the display panel assembly in the ACF attachment unit, and compressing a second COF on the second ACF in the compression unit, while the rotated display panel assembly is transferred in the first direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the invention will become more apparent by describing in further detail exemplary embodiments thereof with reference to the accompanying drawings, in which: 
         FIG.  1    is a plan view illustrating a display device according to an embodiment of the disclosure; 
         FIG.  2    is an enlarged plan view of portion A of  FIG.  1   ; 
         FIG.  3    is a side view of the portion A of  FIG.  1   ; 
         FIG.  4    is a block diagram illustrating a structure of a bonding apparatus according to an embodiment of the disclosure; 
         FIG.  5    is a block diagram illustrating a structure of a bonding apparatus according to an alternative embodiment of the disclosure; and 
         FIGS.  6  to  9    are plan views illustrating a bonding method according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments are shown. This invention may, however, be embodied in many different forms, and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. 
     In the drawings, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity. 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. Thus, a “first” element discussed below could also be termed a “second” element without departing from the teachings of the disclosure. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     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 and/or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Further, an expression that an element such as a layer, region, substrate or plate is placed “on” or “above” another element indicates not only a case where the element is placed “directly on” or “just above” the other element but also a case where a further element is interposed between the element and the other element. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. On the contrary, an expression that an element such as a layer, region, substrate or plate is placed “beneath” or “below” another element indicates not only a case where the element is placed “directly beneath” or “just below” the other element but also a case where a further element is interposed between the element and the other element. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms, including “at least one,” unless the content clearly indicates otherwise. “Or” means “and/or.” “At least one of A and B” means “A and/or B.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     “About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). 
     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 having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a plan view illustrating a display device according to an embodiment of the disclosure. 
     Referring to  FIG.  1   , an embodiment of the display device  1000  includes a display panel  900  and a driver  300 . The display panel  900  may include a thin film transistor (“TFT”) substrate  100  and a counter substrate  200 . The display panel  900  may include a display area DA, in which the TFT substrate  100  and the counter substrate  200  overlap each other, and a peripheral area PA, in which the TFT substrate  100  and the counter substrate  200  do not overlap each other when viewed from a plan view in a thickness direction of the display panel  900 . 
     The TFT substrate  100  may include gate lines GL 1  to GLn, source lines SL 1  to SLm, and sub-pixels (or pixels) PX connected to the gate lines GL 1  to GLn and the source lines SL 1  to SLm. 
     The driver  300  includes a source driving circuit  320  and a gate driving circuit  310 . The driver  300  is disposed in the peripheral area PA to provide a gate signal and a source signal, which are provided from a printed circuit board (“PCB”)  2000 , respectively to the gate lines GL 1  to GLn and the source lines SL 1  to SLm. 
     The driver  300  is disposed on or adhered to the peripheral area PA of the display panel  900 .  FIG.  1    shows an embodiment in which the gate driving circuit  310  is provided or formed at only one side of the display area DA. Alternatively, the gate driving circuit  310  may be provided at one side or both sides of the display area DA to be connected to the gate lines GL 1  to GLn. The source driving circuit  320  may be provided or formed at an upper side of the display area DA to be connected to one ends of the source lines SL 1  to SLm. 
     In an embodiment, three source driving circuits  320  and three gate driving circuit  310  may be provided as illustrated in  FIG.  1   , but the disclosure is not limited thereto. 
       FIG.  2    is an enlarged plan view of portion A of  FIG.  1   .  FIG.  3    is a side view of the portion A of  FIG.  1   . 
     Referring to  FIGS.  1  to  3   , an embodiment of the display device  1000  includes a display panel assembly  110 , source connection pads SP 1  and SP 2  and source driving circuits  321  and  322 . 
     The display panel assembly  110  may include the TFT substrate  100 , in which at least one sub-pixel PX 1  and PX 2  is disposed, and the counter substrate  200 . The TFT substrate  100  may be provided in the display area DA on the counter substrate  200 . 
     A plurality of sub-pixels PX 1  and PX 2  are defined or formed in the display area DA. The sub-pixels PX 1  and PX 2  may be connected to source lines SL 1  and SL 2 , respectively. In an embodiment, as shown in  FIG.  2   , a first sub-pixel PX 1  and a second sub-pixel PX 2  are disposed on different rows that do not overlap each other in a horizontal direction. 
     The source connection pads SP 1  and SP 2  extending from the source lines SL 1  and SL 2 , respectively, may be disposed or formed in the peripheral area PA on the TFT substrate  100 . In an embodiment, as shown in  FIG.  2   , a first source connection pad SP 1  extends from a first source line SL 1  connected to the first sub-pixel PX 1 , and a second source connection pad SP 2  extends from a second source line SL 2  connected to the second sub-pixel PX 2 . In such an embodiment, the first source connection pad SP 1  and the second source connection pad SP 2  may be disposed on different rows that do not overlap each other in a horizontal direction. Herein, the horizontal direction may be a direction perpendicular to an extending direction of the source lines SL 1  and SL 2  when viewed from the plan view as shown in  FIG.  2   . 
     The source driving circuits  321  and  322  may be formed with a chip-on-film (“COF”) that includes a base film (not shown) and a plurality of conductive lead lines (not shown) formed on the base film. The base film may be an insulating film including or made of polyimide or the like. The conductive lead lines may include or be made of a conductive material such as copper (Cu), nickel (Ni) or gold (Au). 
     Some conductive lead lines (e.g., input-side lead lines) among the conductive lead lines may be electrically connected to the source lines SL 1  and SL 2  through the source connection pads SP 1  and SP 2  when the base film is attached to the source connection pads SP 1  and SP 2 . In an embodiment, a conductive lead line of a first source driving circuit  321  may be electrically connected to the first source connection pad SP 1 . In addition, a conductive lead line of a second source driving circuit  322  may be electrically connected to the second source connection pad SP 2 . 
     In an embodiment, the second source driving circuit  322  may have an area wider than that of the first source driving circuit  321  as shown in  FIG.  3    to be electrically connected to the second source connection pad SP 2  disposed on a row different from that of the first source connection pad SP 1 . 
     The source driving circuits  321  and  322  extend to the outside of the TFT substrate  100 , to be adhered to the PCB  2000 . Some conductive lead lines (e.g., output-side lead lines) provided at an extension part among the conductive lead lines of the source driving circuits  321  and  322  may be electrically connected to the PCB  2000 . 
     The source driving circuits  321  and  322  may be attached to the source connection pads SP 1  and SP 2  through an anisotropic conductive film ACF, using a tape automated bonding (“TAB”) process. 
     The anisotropic conductive film ACF may include a polymer resin PL cured by heat and conductive particles CP dispersed in the polymer resin PL. When heat and pressure are applied to the anisotropic conductive film ACF, the polymer resin PL may be melted, and the conductive particles CP may electrically connect the conductive lead lines and the source connection pads SP 1  and SP 2 . Thus, the anisotropic conductive film ACF has both conductivity and adhesive properties. The conductive particles CP may include a metal such as carbon fiber, nickel (Ni), and platinum (Pt), or a compound thereof. In such an embodiment, the polymer resin PL may include styrene butadiene rubber, polyvinyl, butylene, epoxy resin, polyurethane, or acrylic resin. 
     The anisotropic conductive film ACF is interposed between the source driving circuits  321  and  322  and the source connection pads SP 1  and SP 2  to electrically and physically connect the source driving circuits  321  and  322  to the source connection pads SP 1  and SP 2 . 
     In an embodiment, although not shown in the drawings, the gate driving circuit  310  of  FIG.  1    may be attached onto the display panel assembly  110 , using a method identical or similar to that used for attaching the source driving circuit  320 . 
     Hereinafter, embodiments of a bonding apparatus and a bonding method for attaching the source driving circuits  321  and  322  onto the display panel assembly  110  will be described in detail. 
       FIG.  4    is a block diagram illustrating a structure of a bonding apparatus according to an embodiment of the disclosure.  FIG.  5    is a block diagram illustrating a structure of a bonding apparatus according to an alternative embodiment of the disclosure. Referring to  FIGS.  4  and  5   , embodiments of the bonding apparatus according to the disclosure includes a COF adhesion process unit  10  and a PCB adhesion process unit  20 . 
     A gate adhesion unit  11  performs a process of adhering or connecting the gate driving circuit  310  to a gate connection pad formed on the display panel assembly  110 . The adhesion of the gate driving circuit  310  may be performed using a method identical or similar to that used for bonding the source driving circuit  320 , but a detailed process method is not particularly limited. Alternatively, the gate adhesion unit  11  may be omitted. 
     A source adhesion unit  12  may include an ACF attachment unit  121 , a preliminary compression unit  122 , a primary compression unit  123 , a buffer unit  124 , a first ACF transfer unit  125 , a second ACF transfer unit  126 , a first COF transfer unit  127  and a second COF transfer unit  128 . 
     The ACF attachment unit  121  attaches an ACF on the source connection pads SP 1  and SP 2  disposed or formed on the display panel assembly  110 . In embodiments of the disclosure, the ACF attachment unit  121  may receive an ACF transferred from the first ACF transfer unit  125  or the second ACF transfer unit  126 , and attach the transferred ACF onto the source connection pads SP 1  and SP 2  of the display panel assembly  110 . In one embodiment, for example, the ACF attachment unit  121  may attach a first ACF transferred from the first ACF transfer unit  125  onto the source connection pads SP 1  and SP 2  during a first TAB process which will be described later, and attach a second ACF transferred from the second ACF transfer unit  126  onto the source connection pads SP 1  and SP 2  during a second TAB process which will be described later. 
     The preliminary compression unit  122  may preliminarily compress a COF defining the source driving circuits  321  and  322  on an ACF. In embodiments of the disclosure, the preliminary compression unit  122  may preliminarily compress, on the first ACF, a first COF for forming the first source driving circuit  321  and transferred from the first COF transfer unit  127 , and preliminarily compress, on the second ACF, a second COF for forming the second source driving circuit  322  and transferred from the second COF transfer unit  128 . 
     The primary compression unit  123  may primarily compress the preliminarily compressed COF. In embodiments of the disclosure, the primary compression unit  123  may primarily compress the first COF preliminarily compressed on the first ACF, and primarily compress the second COF preliminarily compressed on the second ACF. 
     In embodiments of the disclosure, the preliminary compression unit  122  and the primary compression unit  123  may include a compression head, in which a heat source is installed, and a compression tip attached to one end of the compression head to compress a COF on an ACF. The heat source of the compression head may be, for example, a heating coil, and heat generated from the heat source is applied to the ACF, such that bonding may be more effectively or easily performed through conductive particles in the ACF. The compression tip may compress the COF toward the ACF while ascending and descending through a tip lifter which may include or be configured with a cylinder or motor. 
     In such an embodiment, configurations of the preliminary compression unit  122  and the primary compression unit  123  are not limited to those described above. In embodiments, the preliminary compression unit  122  and the primary compression unit  123  may not include some of the above-described components, or further include other components. 
     The buffer unit  124  rotates the display panel assembly  110  by about 180 degrees during a retransferring process between the first TAB process and the second TAB process, which will be described later. In an embodiment, the buffer unit  124  may include an ascending/descending member for allowing the display panel assembly  110  to ascend/descend and a rotating member for rotating the display panel assembly  110 . In one embodiment, for example, the ascending/descending member may hold the display panel assembly  110  and allow the display panel assembly  110  held by pressure of the cylinder or rotary power of the motor to ascend or descend. In an embodiment, the rotating member may include, for example, a motor for rotating the display panel assembly  110  by about 180 degrees in interlock with the ascending/descending member, and the like. 
     However, the configuration of the buffer unit  124  is not limited thereto, but the buffer unit  124  may have any component capable of rotating the display panel assembly  110  by 180 degrees such that upper and lower sides of the display panel assembly  110  are reversed. 
     In an embodiment, each of the ACF attachment unit  121 , the preliminary compression unit  122 , the primary compression unit  123  and the buffer unit  124  may include or be configured with a conveyor that accommodates the display panel assembly  110  and is transferable in both directions. Each of the conveyors of the ACF attachment unit  121 , the preliminary compression unit  122 , the primary compression unit  123  and the buffer unit  124  transfers (firstly transfers) the display panel assembly  110  in a first direction (i.e., a direction from the gate adhesion unit  11  to the PCB adhesion process unit  20 ) during the first TAB process and the second TAB process. In an embodiment, each of the conveyors of the ACF attachment unit  121 , the preliminary compression unit  122 , the primary compression unit  123  and the buffer unit  124  retransfers (secondly transfers) the display panel assembly  110  in a second direction (i.e., a direction from the PCB adhesion process unit  20  to the gate adhesion unit  11 ) during a conveying process between the first TAB process and the second TAB process. 
     In an embodiment, as shown in  FIG.  4   , the buffer unit  124  may be provided between the gate adhesion unit  11  and the ACF attachment unit  121 , but the disclosure is not limited thereto. In an alternative embodiment, the buffer unit  124  may be provided between the primary compression unit  123  and the PCB adhesion process unit  20  as shown in  FIG.  5   . 
     In an embodiment, when the buffer unit  124  is provided between the gate adhesion unit  11  and the ACF attachment unit  121 , the display panel assembly  110  is transferred via the primary compression unit  123 , the preliminary compression unit  122  and the ACF attachment unit  121  during the above-described transferring process, to be transferred to the buffer unit  124 . The buffer unit  124  may rotate the retransferred display panel assembly  110 . 
     In such an embodiment, when the buffer unit  124  is provided between the primary compression unit  123  and the PCB adhesion process unit  20 , the buffer unit  124  rotates the display panel assembly  110  during the above-described transferring process and then retransfers the rotated display panel assembly  110  to the primary compression unit  123 . Then, the rotated display panel assembly  110  is conveyed via the primary compression unit  123 , the preliminary compression unit  122  and the ACF attachment unit  121 . 
     The PCB adhesion process unit  20  performs a process of allowing the PCB to be adhered to the first COF and the second COF, which are attached onto the display panel assembly  110  transferred from the COF adhesion process unit  10 . The adhesion of the PCB may be performed using a method identical or similar to that used for the source driving circuit  320 , but a detailed process method is not particularly limited. 
       FIGS.  6  to  9    are plan views illustrating a bonding method according to an embodiment of the disclosure. 
     Referring to  FIGS.  1  to  9   , an embodiment of the bonding method may include a first TAB process, a retransferring process and a second TAB process. The display panel assembly  110  is transferred in the first direction (i.e., the direction from the gate adhesion unit  11  to the PCB adhesion process unit  20 ) during the first TAB process and the second TAB process, and is transferred in the second direction (i.e., the direction from the PCB adhesion process unit  20  to the gate adhesion unit  11 ) during the retransferring process. 
     During the first TAB process, the display panel assembly  110  is transferred to the ACF attachment unit  121  in a state in which the gate driving circuit  310  is attached by the gate adhesion unit  11  as shown in  FIG.  6   . In an embodiment, as shown in  FIG.  6   , the gate driving circuit  310  is attached to both sides of the display panel assembly  110 , but not being limited thereto. Alternatively, the gate driving circuit  310  may be attached to only one side of the display panel assembly  110 . 
     The display panel assembly  110  is transferred in a state in which side surfaces, at which the source connection pads SP 1  and SP 2  are formed, are aligned adjacent to the first ACF transfer unit  125 . In an embodiment, when the buffer unit  124  between the gate adhesion unit  11  and the ACF attachment unit  121 , the display panel assembly  110  may be transferred to the ACF attachment unit  121  via the buffer unit  124 . 
     During the first TAB process, the ACF attachment unit  121  attaches a first ACF transferred from the first ACF transfer unit  125  to the first source connection pad SP 1  on the display panel assembly  110 . 
     The preliminary compression unit  122  preliminarily compresses a first COF transferred from the first COF transfer unit  127  on the first ACF, and the primary compression unit  123  primarily compresses the first COF. The first COF is used to form a first source driving circuit  321 , and may include a conductive lead line to be electrically connected to the first source connection pad SP 1 . The first COF attached on the display panel assembly  110  by such a process is illustrated in  FIG.  7   . 
     The retransferring process is performed after the first TAB process. The display panel assembly  110  is rotated and retransferred during the retransferring process. 
     In an embodiment, as shown in  FIG.  4   , the display panel assembly  110  is conveyed to the buffer unit  124  via the preliminary compression unit  122  and the ACF attachment unit  121  from the primary compression unit  123  after the first COF is primarily compressed. The buffer unit  124  rotates the retransferred display panel assembly  110  by 180 degrees and then transfers the rotated display panel assembly  110  to the ACF attachment unit  121 . 
     In an alternative embodiment, as shown in  FIG.  5   , the display panel assembly  110  is transferred to the buffer unit  124  after the first COF is primarily compressed. The buffer unit  124  rotates the conveyed display panel assembly  110  by 180 degrees. Subsequently, the rotated display panel assembly  110  is retransferred to the ACF attachment unit  121  via the primary compression unit  123  and the preliminary compression unit  122  from the buffer unit  124 . 
     The upper and lower sides of the display panel assembly  110  are reversed by the rotation as shown in  FIG.  8   , so that the side surfaces, at which the source connection pads SP 1  and SP 2  are formed, are aligned adjacent to the second ACF transfer unit  126 . 
     The second TAB process is performed after the retransferring process. During the second TAB process, the ACF attachment unit  121  attaches a second ACF transferred from the second ACF transfer unit  126  to the second source connection pad SP 2  on the display panel assembly  110 . The first ACF and the first COF, which are attached in the first TAB process, are interposed between the second ACF and the second source connection pad SP 2 . 
     The preliminary compression unit  122  preliminarily compresses a second COF transferred from the second COF transfer unit  128  on the second ACF, and the primary compression unit  123  primarily compresses the preliminarily compressed second COF. The second COF is used to form the second source driving circuit  322 , and may include a conductive lead line to be electrically connected to the second source connection pad SP 2 . The second COF attached onto the display panel assembly  110  by such a process is illustrated in  FIG.  9   . 
     After the source driving circuits  321  and  322  are adhered onto the display panel assembly  110  as described above, the display panel assembly  110  may be transferred to the PCB adhesion process unit  20 . 
     As described above, according to embodiments of the disclosure, a bonding process may be efficiently performed while not increasing the layout of bonding process facilities through two TAB processes and a retransferring process provided therebetween. 
     Herein, the bonding process for the source driving circuit are described in detail. However, such bonding process may be applied for the gate driving circuit and PCB adhesion without departing from the technical spirit and scope of the disclosure. 
     In embodiments of the bonding apparatus and the bonding method according to the disclosure, the layout of process facilities may be reduced in a TAB process of a COF. 
     Exemplary embodiments of the invention have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as set forth in the following claims.