Patent Publication Number: US-2023154769-A1

Title: Chip transfer apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0158049, filed on Nov. 16, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     The disclosure relates to a chip transfer apparatus. 
     2. Description of the Related Art 
     A micro-semiconductor chip, for example, a light-emitting diode (LED), has low power consumption and is eco-friendly. Due to these advantages, industrial demand for LEDs is increasing. LEDs are being applied not only for lighting devices or LCD backlights, but also for LED display devices. That is, a display device using a micro-unit LED chip is being developed. In manufacturing a micro LED display device, it is necessary to transfer micro LEDs to a substrate. A pick-and-place method is widely used as a method of transferring micro LEDs. However, with this method, as the size of a micro LED becomes smaller and the size of a display increases, productivity is lowered. 
     SUMMARY 
     Provided are apparatuses for transferring a micro-semiconductor chip by a wet method. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented example embodiments of the disclosure. 
     According to an aspect of the disclosure, there is provided a chip transfer apparatus configured to align a plurality of micro-semiconductor chips in a plurality of grooves of a transfer substrate, the chip transferapparatus including: a chip storage module configured to store a suspension including a plurality of micro-semiconductor chips and impurities; a chip filtration module configured to receive the suspension from the chip storage module and separate a first suspension including the plurality of micro-semiconductor chips and a second suspension including the impurities; and a chip supply module configured to supply the first suspension onto the transfer substrate from the chip filtration module, wherein the plurality of micro-semiconductor chips included in the first suspension are flowable on the transfer substrate. 
     The chip filtration module may be further configured to separate the suspension into the first suspension and the second suspension using at least one of sonophoretic dynamics, dielectrophoresis, magnetophoretic dynamics, microfluidic dynamics, centrifugal force, or pinched flow fractionation. 
     At least one of a size and a mass of the impurities may be different from a size or a mass of the micro-semiconductor chips included in the first suspension. 
     The impurities may include a micro-semiconductor chip debris having at least one of a size and a mass different from a size or a mass of the micro-semiconductor chips included in the first suspension. 
     A micro-semiconductor chip debris included in the second suspension may be smaller than the micro-semiconductor chips included in the first suspension. 
     The micro-semiconductor chip debris included in the second suspension may be a partially broken micro-semiconductor chip. 
     The chip filtration module may include an inlet connected to a lower area of the chip storage module, the inlet configured to receive the suspension is introduced from the chip storage module; a channel connected to the inlet and through which the suspension flows; and a first outlet connected to the channel and an upper area of the chip supply module and configured to discharge the first suspension to the chip supply module. 
     The chip filtration module may be formed of a substrate including at least one of silicon, glass, polymer, plastic, or metal, and wherein the channel is embedded in the substrate. 
     An anti-adhesive film may be formed on a surface of the channel, the anti-adhesive film configured to prevent adherence of the micro-semiconductor chips. 
     The anti-adhesive film may be hydrophobic. 
     The chip transfer apparatus may further include a second outlet connected to the channel and configured to discharge the second suspension. 
     The channel may include: a branching area in which the micro-semiconductor chips and the impurities are separated; a first channel through which the suspension flows, the first channel connecting the inlet to the branching area; a second channel through which the first suspension flows, the second channel connecting the branching area to the first outlet; and a third channel through which the second suspension flows, the third channel connecting the branching area to the second outlet. 
     A dimension of the third channel may be smaller than a dimension of the second channel. 
     The third channel may include a first sub-channel and a second sub-channel spaced apart the first sub-channel, and wherein the second channel is provided between the first sub-channel and the second sub-channel. 
     The first sub-channel and the second sub-channel may have a symmetrical structure with respect to the second channel. 
     The chip filtration module may further include a second outlet connected to the channel and configured to discharge a first sub-suspension including impurities smaller than the micro-semiconductor chips in the second suspension; and a third outlet connected to the channel and configured to discharge a second sub-suspension including impurities larger than the micro-semiconductor chips in the second suspension. 
     The channel may include a first branching area and a second branching area spaced apart from the first branching area; a first channel through which the suspension flows, the first channel connecting the inlet to the first branching area; a second channel through which the first suspension and the second sub-suspension flow, the second channel connecting the first branching area to the first branching area; a third channel through which the first sub-suspension flows, the third channel connecting the first branching area to the second outlet; a fourth channel through which the first suspension flows, the fourth channel connecting the second branching area to the first outlet; and a fifth channel through which the second sub-suspension flows, the fifth channel connecting the second branching area to the third outlet. 
     The first channel, the second channel, and the fifth channel may have a same length direction. 
     The chip storage module may include: a stirrer configured to mix the suspension to make a concentration of the micro-semiconductor chips uniform. 
     The micro-semiconductor chips may be light-emitting devices. 
     The light-emitting devices each may include first and second electrodes apart from each other on one surface. 
     According to another aspect of the disclosure, there is provided a chip filtration apparatus including: an inlet configured to receive a first suspension including a plurality of micro-semiconductor chips and a plurality of impurities; a first channel configured to transport the first suspension from the inlet to a junction at which the first suspension is separated into a second suspension including the plurality of micro-semiconductor chips and a third suspension including the plurality of impurities; a second channel connected to the junction and configured to transport the second suspension including the plurality of micro-semiconductor chips; a third channel connected to the junction and configured to transport the third suspension including the plurality of impurities; a first outlet connected to the second channel and configured to receive the second suspension including the plurality of micro-semiconductor chips; and a second outlet connected to the third channel and configured to receive the third suspension including the plurality of impurities. 
     The inlet may be connected to a lower area of a chip storage module. 
     The first outlet may be connected to an upper area of a chip supply module and configured to discharge the second suspension to the chip supply module. 
     The first suspension may be separated into the second suspension and the third suspension using at least one of sonophoretic dynamics, dielectrophoresis, magnetophoretic dynamics, microfluidic dynamics, centrifugal force, or pinched flow fractionation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain example embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a view schematically illustrating a method of transferring a micro-semiconductor chip to a transfer substrate, according to an example embodiment; 
         FIG.  2    is a view for explaining a state in which a suspension is supplied onto a transfer substrate according to an example embodiment; 
         FIG.  3    is a view of a micro-semiconductor chip according to an example embodiment; 
         FIG.  4    is a schematic view of a chip transfer module according to an example embodiment; 
         FIG.  5 A  is a schematic view of a chip filtration module for separating a micro-semiconductor chip using microfluidic dynamics, according to an example embodiment; 
         FIG.  5 B  is a plan view of a channel around a branching area of  FIG.  5 A ; 
         FIG.  5 C  is an equivalent circuit diagram of the channel around a branching area of  FIG.  5 B , 
         FIG.  6    is a view of a chip filtration module according to another example embodiment; 
         FIG.  7    is a view of a chip filtration module according to another example embodiment; 
         FIG.  8    is a schematic view of a chip filtration module based on pinched flow fractionation, according to an example embodiment; 
         FIG.  9    is a schematic view of a chip filtration module based on centrifugal force, according to an example embodiment; 
         FIG.  10    is a schematic view of a chip filtration module based on sound waves, according to an example embodiment; 
         FIGS.  11  to  16    are views for explaining an example of a method of supplying a liquid onto a transfer substrate by a liquid supply module, according to an example embodiment; 
         FIG.  17    is a view for explaining a chip transfer module according to another example embodiment; 
         FIG.  18    is a view of a chip transfer apparatus including a chip transfer module, according to an example embodiment; 
         FIG.  19    is a conceptual diagram for explaining the operation of a chip alignment module according to an example embodiment; 
         FIG.  20    is a view for explaining an example of an absorbent material according to an example embodiment; 
         FIGS.  21  to  23    are views for explaining an operation of a chip alignment module according to an example embodiment; 
         FIGS.  24  and  25    are views illustrating a process in which micro-semiconductor chips having different surface properties are aligned; 
         FIG.  26    is a view for explaining an example in which a chip alignment module according to an example embodiment has a plurality of absorbent materials; 
         FIG.  27    is a view for explaining a state in which a dummy micro-semiconductor chip is present on a transfer substrate; 
         FIGS.  28  and  29    are views for explaining an operation of a cleaning module according to an example embodiment; 
         FIG.  30    is a view for explaining a transfer substrate in a state in which a cleaning operation is completed; 
         FIG.  31    is a view for explaining a pressing member of a cleaning module according to another example embodiment; 
         FIGS.  32  and  33    are views for explaining an example of a cleaning module according to another example embodiment; 
         FIG.  34    is a view for explaining an example of a cleaning module according to another example embodiment; 
         FIG.  35    is a view for explaining an example of a cleaning module according to another example embodiment; 
         FIGS.  36  and  37    are views for explaining an operation of an inspection module according to an example embodiment; 
         FIG.  38    is a view for explaining a configuration for supporting a transfer substrate and a peripheral member thereof in a semiconductor chip transfer apparatus; and 
         FIGS.  37  to  40    are views for explaining an operation of an antistatic module according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to example embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the example embodiments are merely described below, by referring to the figures, to explain aspects. 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. 
     Hereinafter, a chip transfer apparatus according to various example embodiments will be described in detail with reference to the accompanying drawings. The same reference numerals refer to the same elements throughout. In the drawings, the sizes of constituent elements may be exaggerated for clarity. Though terms like ‘first’ and ‘second’ are used to describe various elements, the elements are not limited to these terms. These terms are used only to differentiate an element from another element. 
     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. In addition, it will be understood that when a unit is referred to as “comprising” another element, it does not preclude the possibility that one or more other elements may exist or may be added. In addition, thicknesses or sizes of elements in the drawings are exaggerated for convenience and clarity of description. Furthermore, when an element is referred to as being “on” or “above” another element, it may be directly on the other element, or intervening elements may also be present. Moreover, the materials constituting each layer in the following example embodiments are merely examples, and other materials may be used. 
     In addition, the terms “-er”, “-or”, and “module” described in the specification mean units for processing at least one function and/or operation and can be implemented by hardware components or software components and combinations thereof. 
     The particular implementations shown and described herein are illustrative examples of the disclosure and are not intended to otherwise limit the scope of the disclosure in any way. For the sake of brevity, conventional electronics, control systems, software development and other functional aspects of the systems may not be described in detail. Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. 
     The use of the terms “a,” “an,” and “the” and similar referents is to be construed to cover both the singular and the plural. 
       FIG.  1    is a view schematically showing a method of transferring a micro-semiconductor chip  110  to a transfer substrate  200  according to an example embodiment, and  FIG.  2    is a view for explaining a state in which a suspension  100  is supplied onto the transfer substrate  200  according to an example embodiment. 
     The transfer substrate  200  may include a plurality of grooves h into which at least a portion of the micro-semiconductor chip  110  may be provided. According to an example embodiment, at least a portion of the micro-semiconductor chip  110  may be inserted or placed into a groove, among the plurality of grooves. Each of the plurality of grooves h may have a size into which at least a portion of the micro-semiconductor chip  110  may be provided. For example, a size of a groove h may have a size of a micro unit. For example, the size of the groove h may be less than 1000 μm, for example, 500 μm or less, 200 μm or less, or 100 μm or less. The size of the groove h may be greater than that of the micro-semiconductor chip  110 . 
     Intervals between the plurality of grooves h may correspond to intervals between micro-semiconductor chips  110  inserted or placed into the grooves h. For example, when the micro-semiconductor chip  110  is a light-emitting device, intervals between the plurality of grooves h may correspond to a pixel interval of a display device used in a final product. However, the spacing between the plurality of grooves h is not limited thereto, and may be variously modified as necessary. 
     The transfer substrate  200  may include a plurality of layers. For example, the transfer substrate  200  may include a base substrate  210  and guide barrier ribs  220 . According to an example embodiment, the base substrate  210  and the guide barrier ribs  220  may be made of different materials. However, the disclosure is not limited thereto, and as such, according to another example embodiment, the base substrate  210  and the guide barrier ribs  220  may be made of the same material. However, the configuration of the transfer substrate  200  is not limited to a plurality of layers, and may be a single-layer transfer substrate  200 . In addition, a planar shape of the transfer substrate  200  may be a quadrangle, but is not limited thereto. For example, the planar shape of the transfer substrate  200  may be circular. 
     A chip transfer module  10  may supply the suspension  100  including the plurality of micro-semiconductor chips  110  and a liquid L to the transfer substrate  200  so that the plurality of micro-semiconductor chips  110  are flowable on the transfer substrate  200 . 
     As shown in  FIG.  2   , When the suspension  100  is supplied to the transfer substrate  200 , the liquid L contained in the suspension  100  forms a thin film on the transfer substrate  200 , and at least some of the plurality of micro-semiconductor chips  110  may be in a state immersed in the liquid L. 
     According to an example embodiment, because the plurality of micro-semiconductor chips  110  are immersed in the liquid L, they may be flowable on the transfer substrate  200 . At this time, the liquid L supplied onto the transfer substrate  200  allows the plurality of micro-semiconductor chips  110  to flow, but may be thinly formed on the transfer substrate  200  to prevent or minimize an unintended flow by a chip alignment module  20  to be described later. 
     For example, the liquid L may be maintained on the transfer substrate  200  without a separate configuration (e.g., a water tank, etc.) for maintaining the liquid L on the transfer substrate  200 . The liquid L supplied onto the transfer substrate  200  may have a surface convex upward due to surface tension or the like. A height H of the liquid L may decrease as the liquid L approaches an edge of the transfer substrate  200 . The height H of the liquid L supplied onto the transfer substrate  200  may be less than or equal to  20  times a thickness TH of the micro-semiconductor chip  110 . According to an example embodiment, the height H of the liquid L supplied onto the transfer substrate  200  may be less than or equal to 10 times the thickness TH of the micro-semiconductor chip  110 . However, the disclosure is not limited thereto, and as such, according to an example embodiment, the height H of the liquid L supplied onto the transfer substrate  200  may be less than or equal to 5 times the thickness TH of the micro-semiconductor chip  110 . According to an example embodiment, the height H of the liquid L supplied onto the transfer substrate  200  may be less than or equal to twice the thickness TH of the micro-semiconductor chip  110 . The height H of the liquid L may be an average height. 
     The liquid L may be any type of liquid as long as it does not corrode or damage the micro-semiconductor chip  110 . The liquid L may include, for example, at least one of water, ethanol, alcohol, polyol, ketone, halocarbon, acetone, a flux, or an organic solvent. The organic solvent may include, for example, isopropyl alcohol (IPA). The liquid L is not limited thereto, and various changes are possible. 
     The micro-semiconductor chip  110  may be a member having a size of a micro unit. For example, a width, diameter, or thickness of the micro-semiconductor chip  110  may be about 1000 μm or less, or 200 μm or less, or 100 μm or less, or 50 μm or less. The width, diameter, or thickness of the micro-semiconductor chip  110  may be about 1 μm or more. 
     The micro-semiconductor chip  110  may be a micro light-emitting device. However, the micro-semiconductor chip  110  is not limited thereto, and may be a member having a size of a micro unit. For example, the micro-semiconductor chip  110  may be a pressure sensor, a photodiode, a thermistor, a piezoelectric element, or the like. 
     The micro-semiconductor chip  110  may have a symmetrical planar shape. For example, the planar shape of the micro-semiconductor chip  110  may be a square, a circle, a triangle, or a cube. 
       FIG.  3    is a view of the micro-semiconductor chip  110  according to an example embodiment. Referring to  FIG.  3   , an electrode  111  may be arranged at one of the surfaces of the micro-semiconductor chip  110 . The electrode of the micro-semiconductor chip  110  may have a symmetrical structure. For example, a first electrode  111  of the micro-semiconductor chip  110  may be arranged in the center of the micro-semiconductor chip  110 , and the second electrode  113  may be apart from the first electrode  111  and arranged at the periphery of the of the micro-semiconductor chip  110 . As such, even if the micro-semiconductor chip  110  rotates while the micro-semiconductor chip  110  is aligned with the groove h in a later operation, the electrodes of the micro-semiconductor chip  110  may be arranged at a certain position. 
     The chip transfer module  10  may simultaneously supply the liquid L and the micro-semiconductor chip  110  in the form of the suspension  100 . 
       FIG.  4    is a view schematically illustrating a chip transfer module  10  according to an example embodiment. Referring to  FIG.  4   , the chip transfer module  10  may include a chip storage module  310  in which the suspension  100  may be stored. According to an example embodiment, the suspension  100  includes a mixture of the plurality of micro-semiconductor chips  110  and the liquid L. That is, the chip storage module  310  includes the suspension  100  in which the plurality of micro-semiconductor chips  110  and the liquid L are mixed. 
     In the suspension  100  stored in the chip storage module  310 , the plurality of micro-semiconductor chips  110  have a greater specific gravity (or relative density) than that of the liquid L. The specific gravity (or the relative density) of the micro-semiconductor chip  110  may be 2 times or more of the specific gravity (or relative density) of the liquid L. However, the disclosure is not limited thereto, and as such, the specific gravity of the micro-semiconductor chip  110  may be, for example, 4 times or more, or for example, 6 times or more of the specific gravity (or the relative density) of the liquid L. The specific gravity (or the relative density) of the micro-semiconductor chip  110  may be 40 times or less of the specific gravity (or the relative density) of the liquid L. 
     As such, when the specific gravity (or the relative density) of the micro-semiconductor chip  110  is greater than the specific gravity (or the relative density) of the liquid L, the plurality of micro-semiconductor chips  110  may be in a sinking state before being discharged from the chip storage module  310 . For example, the plurality of micro-semiconductor chips  110  may be clustered in a lower area of the chip storage module  310 . In this state, when the suspension  100  is discharged from the chip storage module  310 , a discharge amount of the micro-semiconductor chip  110  may not be constant. In particular, if there is an outlet in the lower area of the chip storage module  310 , a large amount of the micro-semiconductor chip  110  may be unintentionally discharged at once. 
     To prevent this from happening, the chip storage module  310  may be configured such that the plurality of micro-semiconductor chips  110  included in the suspension  100  are evenly mixed. 
     For example, the chip storage module  310  may include a stirrer  312  arranged inside the suspension  100  to mix the suspension  100 . The stirrer  312  may be configured not to damage the micro-semiconductor chip  110  despite collision with the micro-semiconductor chip  110 . For example, the stirrer  312  may have less strength than the micro-semiconductor chip  110 , or may have a greater elastic deformation force. As another example, the micro-semiconductor chip  110  may be mixed by applying vibration to the chip storage module  310  or rotating the chip storage module  310 . 
     In the suspension  100  included in the chip storage module  310 , an impurity  120  other than the micro-semiconductor chip  110  may be further present. For example, after growing and separating the micro-semiconductor chip  110  on a silicon or sapphire substrate, in a process of placing the separated micro-semiconductor chip  110  in the liquid L to make the suspension  100 , the impurity  120 , which is a material other than the micro-semiconductor chip  110 , may enter together. As another example, in a process of mixing the suspension  100  to have a uniform concentration, the micro-semiconductor chips  110  collide with the stirrer  312  or the micro-semiconductor chips  110  collide with each other, thereby generating the impurity  120  as fragments. Accordingly, the impurity  120  is a material different from that of the micro-semiconductor chip  110  in at least one of a size and a mass. The impurity  120  may be a material different from that of the micro-semiconductor chip  110 , and may be a portion of the micro-semiconductor chip  110 , that is, a broken micro-semiconductor chip  110 . 
     As another example, different types of micro-semiconductor chips may be wet-transferred with the same chip transfer module  10 . The micro-semiconductor chip used in the previous wetting transfer process may remain in the chip storage module  310 , and an unwanted micro-semiconductor chip  110  may be erroneously transferred to the transfer substrate  200 . The above-described other types of micro-semiconductor chips may have different sizes, masses, etc. compared to the current micro-semiconductor chip  110  to be transferred, and the previously used micro-semiconductor chips may be the impurity  120  from a viewpoint of the current micro-semiconductor chip  110  to be transferred. 
     When impurities  120  undesirably included in a suspension storage process, the impurities  120  that may be generated during a stirring process, and impurities that are other micro-semiconductor chips remaining in the previous transfer process are transferred together, a transfer yield of the chip transfer module  10  is lowered. 
     The chip transfer module  10  according to an example embodiment may further include a chip filtration module  320  that separates the micro-semiconductor chip  110  and the impurity  120  from the suspension  100 . In the chip filtration module  320 , the suspension  100  is introduced from the chip storage module  310 . The chip filtration module  320  may provide only the first suspension to a chip supply module  330  by separating the first suspension including the micro-semiconductor chip  110  and the second suspension including the impurity  120  from the suspension  100 . In the chip transfer module  10 , the micro-semiconductor chip  110  having certain requirements is supplied to the transfer substrate  200 , so that the transfer yield may be increased. 
     The chip filtration module  320  may include an inlet  321  through which the suspension  100  is introduced from the chip storage module  310 , a channel  322  through which the suspension  100  flows, and a first outlet  323  for discharging the first suspension including the microphone semiconductor chip  110  to the chip supply module  330 . The chip filtration module  320  may further include a second outlet  324  for discharging the second suspension including the impurity  120 . 
     The inlet  321  may be connected to a lower area of the chip storage module  310 , and the first outlet  323  may be connected to an upper area of the chip supply module  330 . A difference in pressure allows the suspension  100  to naturally pass through the chip filtration module  320 . In addition, the second outlet  324  may be connected to an impurity storage module  340 . The second outlet  324  may be connected to an upper area of the impurity storage module  340  so that the second suspension may move naturally by pressure and be stored in the impurity storage module  340 . 
     According to an example embodiment, the sizes of the inlet  321 , the channel  322 , and the first outlet  323  and the second outlet  324  of the chip filtration module  320  may be greater than a size of the micro-semiconductor chip  110 . For example, the sizes of the channel  322 , the inlet  321 , and the first outlet  323  and the second outlet  324  may be within a range of 100 μm to 1000 μm. 
     The chip filtration module  320  may be formed on a substrate formed of at least one of silicon, glass, polymer, plastic, or metal, and the channel  322  of the chip filtration module  320  may be embedded in the substrate. For example, the chip filtration module  320  may be formed by bonding a lower substrate having the plurality of channels  322  formed on its surface, and an upper substrate having the inlet  321  and the first outlet  323  and the second outlet  324  formed while covering the channel  322 . The channel  322  of the lower substrate may be formed by forming a negative photoresist on a silicon substrate and then performing partial etching. Alternatively, a plastic plate on which the channel  322  is engraved may be made by injection molding plastic using a patterned metal template. 
     On the other hand, an anti-adhesive film may be formed on an inner wall of at least one of the channel  322 , the inlet  321 , and the first outlet  323  and the second outlet  324  of the chip filtration module  320  to prevent the micro-semiconductor chip  110  from sticking to the inner wall and clogging the inner wall. When the micro-semiconductor chip  110  is a light-emitting device including an electrode, the anti-adhesive film may be hydrophobic. In other words, a hydrophobic anti-adhesive layer may be formed on the inner wall of the channel  322  to prevent a hydrophilic electrode from being attached to the inner wall of the channel  322 . 
     The chip filtration module  320  may separate the micro-semiconductor chip  110  and the impurity  120  using at least one of microfluidic dynamics, sonophoretic dynamics, dielectrophoretic dynamics, magnetophoretic dynamics, a centrifugal force, and pinched flow fractionation. 
       FIG.  5 A  is a schematic view of the chip filtration module  320  for separating the micro-semiconductor chip  110  using microfluidic dynamics according to an example embodiment,  FIG.  5 B  is a plan view of the channel  322  around a branching area of  FIG.  5 A , and  FIG.  5 C  is an equivalent circuit diagram of the channel  322  around a branching area of  FIG.  5 B . 
     The chip filtration module  320  according to an example embodiment may separate the micro-semiconductor chip  110  in a continuous flow of the suspension  100  using microfluidic dynamics. The chip filtration module  320  may include the inlet  321  through which the suspension  100  is introduced from the chip storage module  310 , the channel  322  connected to the inlet  321  and through which the suspension  100  flows, the first outlet  323  connected to the channel  322  and discharging a first suspension to the chip supply module  330 , and the second outlet  324  connected to the channel  322  and discharging the second suspension to the outside. 
     The channel  322  may include a branching area BR, a first channel CH 1  connecting the inlet  321  to the branching area BR, a second channel CH 2  connecting the branching area BR to the first outlet  323 , and a third channel CH 3  connecting the branching area BR to the second outlet  324 . All of the first to third channels CH 1 , CH 2 , and CH 3  may be connected to the branching area BR, and the first channel CH 1  and the second channel CH 2  may have the same length direction. According to an example embodiment, the branching area BR may provide a path for the micro-semiconductor chip  110  and a path of impurities  120 . 
     The third channel CH 3  may include first and second sub-channels CH 31  and CH 32  apart from each other with the second channel CH 2  therebetween. The first and second sub-channels CH 31  and CH 32  may have a symmetrical structure with respect to the second channel CH 2 . The dimension of the first channel CH 1  may be greater than the dimension of the second and third channels CH 3 , and the dimension of the second channel CH 2  may be greater than the dimension of the third channel CH 3 . 
     Referring to  FIG.  5 B , in the branching area BR where the first channel CH 1 , the second channel CH 2 , and the third channel CH 3  meet, a flow rate Q 1  for the suspension  100  of the first channel CH 1  is divided into flow rates Q 2  and Q 3  for the first suspension and the second suspension flowing into the second channel and the third channel. 
     When an incompressible fluid flows in a laminar flow with pressure actuation, a flow profile in a channel may be parabolic. Thus, a volumetric flow rate Q in each of the channels CH 1 , CH 2 , and CH 3  may be expressed by Equation 1 below. 
     
       
         
           
             
               
                 
                   Q 
                   = 
                   
                     
                       Δ 
                       ⁢ 
                       P 
                       × 
                       
                         D 
                         r 
                         2 
                       
                       ⁢ 
                       
                         wd 
                         
                           32 
                           ⁢ 
                           μ 
                           ⁢ 
                           L 
                         
                       
                     
                     = 
                     
                       Δ 
                       ⁢ 
                       P 
                       × 
                       
                         
                           1 
                           
                             R 
                             h 
                           
                         
                         . 
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                         
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
     Where ΔP is a pressure difference at both ends of each channel, D r  is a hydraulic diameter of each channel, w is a width of the channel  322 , d is a depth of the channel  322 , μ is viscosity of a fluid, that is, the suspension  100 , and L is a length of the channel  322 . In addition, Rh is hydrodynamic resistance of the channel  322 . 
     When a cross section of each channel is a rectangle, the mathematical diameter of the channel is expressed by Equation 2 below. 
         D   r =2 wd  /( w+d )   [Equation 3]
 
     A flow rate distribution in the branching area BR that determines a path of particles included in the suspension  100 , that is, the micro-semiconductor chip  110  and the impurity  120 , may be the same as an electric circuit approximation channel network of  FIG.  5 C . That is, when a ratio of the flow rate Q 1  in the first channel CH 1  to the flow rate Q 2  in the second channel CH 2  is α, it is α=R c2  /(2 R c1  +R c2 ) with reference to  FIG.  5 C . 
     When a flow profile is perfectly parabolic as shown in  FIG.  5 B  and the distribution of particles in a channel depth direction is negligible, a ratio of a volumetric flow rate is equal to a ratio of the area of a parabolic distribution and a ratio of the reciprocal of hydrodynamic equivalent resistance, as shown in  FIG.  4    below. 
         Q   2   ; Q   1  =α:(1 −α)/2 =S   2   ; S   3 =1 /R   c1 ; 1 /R   c2 ,   [Equation 4]
 
     Accordingly, in the parabolic profile, a width W 3  of the second suspension flowing into the third channel CH 3  may be inferred from a width W 1  and α of the first channel CH 1 . Particles having a diameter greater than the virtual width W 3  may not flow into the third channel CH 3  but may flow into the second channel CH 2 . Moreover, a width W 2  may correspond to a portion of the width Wi after the width W 3  is subtracted from both sides of width W 1 . For instance, W 2  =W 1  −(2 *W 3 ). 
     Particles separated and discharged through the first outlet  323  and the second outlet  324  by the principle of microfluidic dynamics may be determined by the size of the channel  322 . In more detail, by adjusting a width, depth, and length of the channel  322  of the chip filtration module  320  and pressure of the suspension  100  flowing through the chip filtration module  320 , the suspension  100  may pass through the second channel CH 2  and the impurity  120  may pass through the third channel CH 3 . For example, the first outlet  323  may discharge a first suspension  101  including the micro-semiconductor chip  110  through the second channel CH 2 , and the second discharge port  324  may discharge a second suspension  102  including the impurity  120  through the third channel CH 3 . 
       FIG.  6    is a view of a chip filtration module  320   a  according to another example embodiment. 
     Referring to  FIG.  6   , the chip filtration module  320   a  may include the inlet  321  through which the suspension  100  is introduced from the chip storage module  310 , the channel  322  connected to the inlet  321  and through which the suspension  100  flows, a plurality of first outlets  323  connected to the channel  322  and discharging a first suspension to the chip supply module  330 , and the second outlet  324  connected to the channel  322  and discharging the second suspension to the outside. 
     The channel  322  may include a plurality of branching areas BR, a plurality of first channels CH 1  connecting the inlet  321  to the branching areas BR, a plurality of second channels CH 2  connecting the first channels CH 1  to the first outlets  323 , and a plurality of third channels CH 31 , CH 32 , and CH 32  connecting the branching areas BR to the second outlet  324 . All of the first to third channels CH 1 , CH 2 , and CH 3  may be connected to the branching area BR, and the first channel CH 1  and the second channel CH 2  may have the same length direction. 
     The third channel CH 3  may include the first and second sub-channels CH 31  and CH 32  from each other with the plurality of second channels CH 2  therebetween, and the third sub-channel CH 33  arranged between the second channels CH 2 . As described above, because the chip filtration module  320  has a structure having a plurality of flow paths from one flow path, the amount of chip filtration processing may be increased, and more micro-semiconductor chips  110  may be simultaneously transferred, thereby reducing the transfer time. 
       FIG.  7    is a view illustrating a chip filtration module  320   b  according to another example embodiment. 
     The chip filtration module  320   b  of  FIG.  7    may separate the micro-semiconductor chip  110  and the impurity  120  as well as further subdivide and separate the impurity  120 . According to an example embodiment, the impurity  120  may include the micro-semiconductor chip debris. The impurity  120  may be greater or smaller in size or mass than the micro-semiconductor chip  110 . When the impurity  120  is generated by fragments of the micro-semiconductor chip  110  during a stirring process of the micro-semiconductor chip  110 , the size of the impurity  120  may be generally smaller than that of the micro-semiconductor chip  110 . However, a micro-semiconductor chip used in another transfer process may be greater than the micro-semiconductor chip  110  to be transferred. When the micro-semiconductor chip  110  is separated by the chip filtration modules  320  and  320   a  according to  FIGS.  5 A and  6   , impurities larger than the micro-semiconductor chip  110  may be introduced into the chip supply module  330  without being separated. 
     As shown in  FIG.  7   , the chip filtration module  320   b  may include the inlet  321  through which the suspension  100  is introduced from the chip storage module  310 , the channel  322  through which the suspension  100  flows, the first outlet  323  for discharging a first suspension including the micro-semiconductor chip  110  to the chip supply module  330 , a second outlet  324   a  for discharging a second suspension including the impurity  120  smaller than the micro-semiconductor chip  110 , a third outlet  324   b  for discharging third suspension  103  including the impurity  120  greater than the micro-semiconductor chip  110  to the outside. 
     The channel  322  may include a plurality of branching areas BR 1  and BR 2  separating the micro-semiconductor chip  110  and the impurity  120 . For example, the channel  322  may include a first branching area BR 1  separating the micro-semiconductor chip  110  and the impurity  120  smaller than the micro-semiconductor chip  110 , and a second branching area BR 2  separating the micro-semiconductor chip  110  and the impurity  120  greater than the micro-semiconductor chip  110 . 
     The channel  322  may include a first channel CH 1  connecting the inlet  321  to the first branching area BR 1 , a second channel CH 2  connecting the first branching area BR 1  to the second branching area BR 2 , the third channel CH 3  connecting the first channel CH 1  to the second outlet  324 , a fourth channel CH 4  connecting the second branching area BR 2  to the second outlet  324 , and a fifth channel CH 5  connecting the second branching area BR 2  to a third outlet  325 . 
     From the chip storage module  310 , the suspension  100  including the micro-semiconductor chip  110  and the impurity  120  is introduced into the channel  322  through the inlet  321 , an impurity (hereinafter referred to as a ‘first impurity’) smaller than the micro-semiconductor chip  110  in the suspension  100  may be separated from the first branching area BR 1  by microfluidic dynamics, and the second suspension including the separated first impurity may be discharged to the second outlet  324  through the third channel CH 3 . Suspension from which the first impurity has been removed, that is, suspension including the micro-semiconductor chip  110  and the impurity  120  (hereinafter referred to as ‘second impurity’) greater than the micro-semiconductor chip  110 , may pass through the second channel CH 2  and reach the second branching area BR 2 . In the second branching area BR 2 , the micro-semiconductor chip  110  and the second impurity are separated by microfluidic dynamics, and the suspension including the micro-semiconductor chip  110  is introduced into the first outlet  324  through the fourth channel CH 4 . In addition, the suspension including the second impurity  120  is introduced into the third outlet  325  through the fifth channel CH 5 . 
     The first outlet  323  may be connected to the chip supply module  330 , and the second and third outlets  324  and  325  may be connected to the impurity storage module  340 . Thus, the chip supply module  330  may transfer the micro-semiconductor chip  110  to the transfer substrate  200 . Because the chip filtration module  320   b  includes a plurality of branching areas, the impurity  120  may be separated in more detail to increase chip filtration efficiency. 
     It is not necessary to include a plurality of branching areas to separate impurities or micro-semiconductor chips in detail. Even with a single branching area, impurities may be separated in detail. 
       FIG.  8    is a schematic view of a chip filtration module  320   c  based on pinched flow fractionation according to an example embodiment. The chip filtration module  320   c  shown in  FIG.  8    may include a plurality of inlets, a plurality of channels, and a plurality of outlets. For example, the chip filtration module  320   c  may include a first inlet IN 1  through which the suspension  100  including the micro-semiconductor chip  110  and the impurity  120  applied from the chip storage module  310  is introduced, a second inlet IN 2  through which only particle-free liquid flows in, a channel CH 1  through which the suspension  100  and the liquid L flow, a channel CH 2  through which the particle-free liquid flows, first to fourth outlets OUT 1 , OUT 2 , OUT 3 , and OUT 4  through which micro-semiconductor chips  110  or impurities  120  having different sizes are discharged, respectively, and a channel  322  connecting between the first to fourth outlets OUT 1 , OUT 2 , OUT 3 , and OUT 4  and channels CH 1  and CH 2 . 
     The channel  322  may include the branching area BR in which micro-semiconductor chips  110  or impurities  120  having different sizes or masses are separated according to pinched flow fractionation. In addition, the channel  322  may include the first channel CH 1  connected to the first inlet IN 1 , the second channel CH 2  connected to the second inlet IN 2 , the branching area BR, and the third to sixth channels CH 3 , CH 4 , CH 5 , and CH 6  respectively connected to the first to fourth outlets OUT 1 , OUT 2 , OUT 3 , and OUT 4 . The first channel CH 1  may include a confluence area JN in which the suspension  100  and the liquid L respectively introduced through the first and second inlets IN 1  and IN 2  meet. 
     The suspension  100  may be introduced through the first inlet IN 1 , and the liquid L may be introduced through the second inlet IN 2 . The liquid L may be a liquid contained in the suspension  100 . However, the disclosure is not limited thereto. The suspension  100  and the liquid L meet in the confluence area JN in the first channel CH 1 , and particles included in the suspension  100 , that is, the micro-semiconductor chip  110  and the impurities  120 , form different streamlines depending on the size or mass. For example, when the suspension  100  and the liquid L meet in the confluence area JN, a streamline may be sequentially formed from small particles to large particles in a direction of the liquid L in the suspension  100 . Thus, the smallest particle may be discharged through the first outlet OUT 1  and the largest particle may be discharged through the fourth outlet OUT 4 . Any one of the first to fourth outlets OUT 1 , OUT 2 , OUT 3 , and OUT 4  may discharge a micro-semiconductor chip having a constant size. 
     According to an example embodiment, the chip filtration module  320   c  may separate the micro-semiconductor chip  110  and the impurity  120  by a centrifugal force.  FIG.  9    is a schematic view of a chip filtration module  320   d  based on a centrifugal force according to an example embodiment. The chip filtration module  320   d  illustrated in  FIG.  9    may include an inlet IN, the channel CH, and the first to third outlets OUT 1 , OUT 2 , and OUT 3 . 
     The channel CH may include the branching area BR in which micro-semiconductor chips  110  or impurities  120  having different sizes or masses are separated according to a centrifugal force. In addition, the channel CH may include the first channel CH 1  connecting the inlet IN to the branch area BR, and the second to fourth channels CH 2 , CH 3 , and CH 4  respectively connecting the branching area BR to the first to third outlets OUT 1 , OUT 2 , and OUT 3 . In particular, the first channel CH 1  may have a spiral shape. 
     When the suspension  100  is introduced through the inlet IN, the suspension  100  is subjected to a centrifugal force while flowing through the spiral first channel CH 1 . Thus, as the first channel CH 1  goes from the center to the outside, large particles included in the suspension  100  may be arranged. Accordingly, the first outlet  323  may discharge the smallest particles (impurities or micro-semiconductor chips), and the third outlet may discharge the largest particles (impurities or micro-semiconductor chips). Any one of the first to third outlets OUT 1 , OUT 2 , and OUT 3  may discharge micro-semiconductor chips  100  having constant sizes. 
     Although it has been said that the micro-semiconductor chip  110  and the impurity  120  included in the suspension  100  are separated by the structure of the chip filtration module  320  so far, the disclosure is not limited thereto. The micro-semiconductor chip  110  and the impurity  120  may be separated even by an active external force. The active external force may be sonophoretic dynamics, magnetophoretic dynamics, or the like. The micro-semiconductor chip  110  and the impurity  120  may be separated by at least one of a structure of a chip filtration module and an active external force. 
       FIG.  10    is a view schematically illustrating a chip filtration module  320   e  based on sound waves according to an example embodiment. Referring to  FIG.  10   , the chip filtration module  320   e  may include the first inlet IN 1  through which the suspension  100  is introduced, second and third inlets IN 2  and IN 3  through which a liquid flows, the channel CH through which the suspension  100  and the liquid flow, the first outlet OUT 1  through which small particles are discharged, and the second and third outlets OUT 2  and OUTS through which large particles are discharged. 
     In addition, the chip filtration module  320   e  may further include a sound wave providing unit  400  that provides a sound wave to the channel CH. The sound wave providing unit  400  may include a sound wave generator  410  arranged on a first sidewall of the channel CH and a reflector  420  arranged on a second sidewall facing the first sidewall of the channel CH. The sound wave generator  410  may be a transducer. A sound wave generated by the sound wave generator  410  may travel across the channel CH and be reflected by the reflector  420 . The reflected sound wave may form a standing wave in the channel CH together with the sound wave generated by the sound wave generator  410 . 
     When the suspension  100  including the micro-semiconductor chip  110  and the impurity  120  is introduced through the first inlet IN 1 , the suspension  100  flows through the channel CH. The sound wave providing unit  400  may provide an ultrasonic wave to the suspension  100 . The ultrasonic wave may be a standing wave. Due to mechanical properties of the micro-semiconductor chip  110  and the impurity  120 , a difference in the force exerted by the ultrasonic wave on the micro-semiconductor chip  110  and the impurity  120  occurs. For example, a small amplitude may be formed at the edge of the channel CH, and a large amplitude may be formed in the central area of the channel CH. Thus, particles having a large size or mass from among the particles included in the suspension  100  converge to the edge of the channel CH as they pass through the channel CH, and particles having a small size or mass from among the particles included in the suspension  100  converge to the central area of the channel  322  as they pass through the channel  322 . 
     Therefore, small particles may be discharged through the first outlet OUT 1  connected to the central area of the channel  322 , and large particles may be discharged through the second and third outlets OUT 2  and OUT 3  connected to the edge of the channel CH. When a large particle is the micro-semiconductor chip  110 , the micro-semiconductor chip  110  may be discharged through the first outlet OUT 1 . 
     Although it has been said that the micro-semiconductor chip  110  and the impurity  120  are discharged through different outlets, the disclosure is not limited thereto. The micro-semiconductor chip  110  and the impurity  120  may be discharged through the same outlet. In this case, a separation effect may be obtained by discharging the micro-semiconductor chip  110  and the impurity  120  with a time difference. For example, the channel  322  may have a curved shape in a vertical direction of a substrate, and a surface acoustic wave may be provided to the channel  322 . Particles are separated at a pressure point caused by superposition of surface acoustic waves, so that small-sized particles may flow rapidly through the channel  322 , and large-sized particles may flow relatively slowly. Therefore, the impurity  120  and the micro-semiconductor chip  110  may be sequentially discharged according to time through one outlet. 
     In addition, when the micro-semiconductor chip  110  has magnetism, a non-magnetic impurity  120  may be separated by an externally applied magnetic field. Alternatively, the micro-semiconductor chip  110  and the impurity  120  may be separated in the channel  322  by dielectrophoresis. 
     Referring back to  FIG.  4   , the chip transfer module  10  may further include the chip supply module  330  for supplying the first suspension on the transfer substrate  200  such that the first suspension including the micro-semiconductor chip  110  may be introduced from the chip filtration module  320  and the micro-semiconductor chip  110  may flow on the transfer substrate  200 . 
     A method in which the chip supply module  330  supplies the first suspension on the transfer substrate  200  may vary. 
       FIGS.  11  to  16    are reference views for explaining methods of supplying a first suspension to a transfer substrate according to an example embodiment. The chip supply module  330  may move the chip supply module  330  in a horizontal direction and/or a vertical direction to evenly supply the first suspension on the transfer substrate  200 . As shown in  FIG.  11   , the chip supply module  330  supplies the first suspension in a dot shape S 1  to a portion of the transfer substrate  200 , and may move the first suspension in a vertical direction Y and a horizontal direction X, or as shown in  FIG.  12   , the chip supply module  330  supplies the first suspension in an elongated shape S 2  in the vertical direction Y, and may move the first suspension in the horizontal direction X. As another example, as shown in  FIGS.  13  and  14   , the chip supply module  330  may supply the first suspension to an area greater than the transfer substrate  200 . 
     As another example, as shown in  FIGS.  15  and  16   , the chip supply module  330  supplies a relatively large amount of the first suspension to a partial area of the transfer substrate  200  in the dot shape S 1  or the elongated shape S 2  in the vertical direction Y. Thereafter, by using a height limiting member  111  such as a blade to evenly spread the first suspension supplied onto the transfer substrate  200 , a thin film may be formed on the transfer substrate  200 . 
       FIG.  17    is a view for explaining a chip transfer module  10   a  according to another example embodiment. Comparing  FIG.  4    and  FIG.  17   , the chip transfer module  10   a  of  FIG.  17    may further include at least one of a concentration measurement module  310   a  for measuring the concentration of a chip in the chip storage module  310  and a chip monitoring module  350  for monitoring a state of the micro-semiconductor chip  110  flowing into the chip supply module  330 . 
     The concentration measuring module  310   a  may measure the concentration of the micro-semiconductor chip  110  in the chip storage module  310  and control a stirrer to operate when the concentration of the micro-semiconductor chip  110  is equal to or greater than a reference value. Therefore, by supplying an excessive amount of micro-semiconductor chips  110  to the chip filtration module  320 , it is possible to prevent the micro-semiconductor chip  110  from blocking the channel  322  in the chip filtration module  320 . 
     Even if the impurityl 20  is removed from the first suspension contained in the micro-semiconductor chip  110 , a separation efficiency of the micro-semiconductor chip  110  and the impurity  120  is reduced due to continuous use of the chip filtration module  320 . The chip monitoring module  350  may monitor a state of the micro-semiconductor chip  110  flowing into the chip supply module  330  and replace the chip filtration module  320  when an abnormality is found. 
       FIG.  18    is a view illustrating a chip transfer apparatus  1  including the chip transfer module  10  according to an example embodiment. In addition to the chip transfer module  10 , the chip transfer apparatus  1  may further include at least one of the chip alignment module  20 , a cleaning module  30 , an inspection module  40 , a recovery module  50 , an antistatic module  60 , and a controller  70  for controlling all operations of the chip transfer apparatus  1 . Because the chip transfer module  10  has been described above, a detailed description thereof will be omitted. Hereinafter, the chip alignment module  20 , the cleaning module  30 , the inspection module  40 , the recovery module  50 , and the antistatic module  60  will be sequentially described. 
     Referring to  FIG.  19   , the chip alignment module  20  includes an absorbent material  21  that absorbs the liquid L. The transfer substrate  200  may be scanned with the absorbent material  21 . The chip alignment module  20  may move the absorbent material  21  along a surface of the transfer substrate  200 . The absorbent material  21  may move along the surface of the transfer substrate  200  while in contact with the transfer substrate  200 . 
     The absorbent material  21  may include, for example, fabric, tissue, polyester fiber, paper, or a wiper. 
     The absorbent material  21  may have a structure in the form of a mesh capable of absorbing the liquid L. Referring to  FIG.  20   , the absorbent material  21  has a plurality of mesh holes, and the size of such a mesh hole may be less than that of the micro-semiconductor chip  110  to prevent the micro-semiconductor chip  110  from being stuck or pinched. 
     The absorbent material  21  may be used alone without other auxiliary devices. However, the disclosure is not limited thereto, and the absorbent material  21  may be coupled to a support  22  to conveniently scan the transfer substrate  200  with the absorbent material  21 . The support  22  may have various shapes and structures suitable for scanning the transfer substrate  200 . The support  22  may include, for example, a rod, a blade, a plate, or a wiper. The absorbent material  21  may be provided on either side of the support  22 , or may have a shape wound around the support  22 . 
     The chip supply module  330  may scan the transfer substrate  200  while the absorbent material  21  presses the transfer substrate  200  to an appropriate pressure. Referring to  FIG.  21   , in a scanning operation, the absorbent material  21  may contact the transfer substrate  200  and pass through the plurality of grooves h. The liquid L may be absorbed by the absorbent material  21  during scanning. 
     Scanning may be performed in various ways including, for example, at least one of a sliding method, a rotating method, a translating motion method, a reciprocating motion method, a rolling method, a spinning method, or a rubbing method of the absorbent material  140 , and may include both a regular method and an irregular method. Alternatively, the scanning may include at least one of a rotational motion, a translational motion, a rolling motion, or spinning of the transfer substrate  200 . Alternatively, the scanning may be performed by cooperation of the absorbent material  21  and the transfer substrate  200 . For example, the scanning may proceed by moving or rotating the transfer substrate  200  while the absorbent material  21  presses the transfer substrate  200 . 
     Scanning the transfer substrate  200  with the absorbent material  21  may include absorbing the liquid L in the plurality of grooves h while the absorbent material  21  passes through the plurality of grooves h. The absorbent material  21  may pass through the plurality of grooves h in contact with the transfer substrate  200 . 
     Referring to  FIG.  22   , when the absorbent material  21  passes through the groove h, the liquid L in the groove h is absorbed, and in the process, the micro-semiconductor chip  110  may be aligned inside the groove h. 
     Referring to  FIG.  23   , the absorbent material  21  absorbs the liquid L present on the transfer substrate  200  while the absorbent material  21  moves along a surface of the transfer substrate  200 . Due to the absorption by the absorbent material  21 , the amount of the liquid L present on the transfer substrate  200  is changed. For example, the amount of the liquid L present in an area  200 - 2  of the transfer substrate  200  through which the absorbent material  21  has passed may be different from the amount of the liquid L present in an area  200 - 1  of the transfer substrate  200  before the absorbent material  21  passes. For example, the amount of the liquid L present in the area  200 - 2  of the transfer substrate  200  through which the absorbent material  21  has passed may be less than the amount of the liquid L present in the area  200 - 1  of the transfer substrate  200  before the absorbent material  21  passes. The liquid L may hardly remain in the area  200 - 2  of the transfer substrate  200  through which the absorbent material  21  has passed. A height of the liquid L present in the area  200 - 2  of the transfer substrate  200  through which the absorbent material  21  has passed is less than a height H 3  of the liquid L present in the area  200 - 1 . 
     According to the relationship between the micro-semiconductor chip  110  and the liquid L, an alignment state of the micro-semiconductor chip  110  may vary. For example, referring to  FIG.  24   , a first end  115  of the micro-semiconductor chip  110  may have a first surface property, and a second end  116  of the micro-semiconductor chip  110  may have a second surface property. The first surface property and the second surface property may be opposite to each other. For example, the first surface property may be lyophobic and the second surface property may be lyophilic. 
     For example, a lyophobic electrode may be arranged at the first end  115  of the micro-semiconductor chip  110 , and the second end  116  of the micro-semiconductor chip  110  may be lyophilic. Because the liquid L is inside the groove h, the micro-semiconductor chip  110  may have a relatively stable posture in which the lyophilic second end  116  faces downward and the lyophobic first end  115  faces upward. Accordingly, the liquid L is absorbed while the absorbent material  21  passes through the groove h while in contact with the surface of the transfer substrate  200 , and the micro-semiconductor chip  110  is aligned with the first end  115  facing upward. 
     When the micro-semiconductor chip  110  is located in the groove h of the transfer substrate  200  with the first end  115  facing down, as shown in  FIG.  25   , the lyophobic first end  115  of the micro-semiconductor chip  110  may be in an unstable state due to contact with the liquid L. Accordingly, the liquid L may be absorbed by the absorbent material  21  while the absorbent material  21  passes through the groove h in a state in which the absorbent material  21  is in contact with the surface of the transfer substrate  200 , or the micro-semiconductor chip  110  may be turned over so that the first end  115  faces upward as shown in  FIG.  24    while the absorbent material  21  presses the micro-semiconductor chip  110 . 
     A scanning process by the absorbent material  21  may be repeated. When the liquid L is absorbed in the scanning process by the absorbent material  21  and the liquid L is insufficient, the supply of the liquid L by the chip supply module  330  may also be repeatedly performed. During this operation, height increase and decrease of the liquid L present on the transfer substrate  200  may be repeatedly performed. 
     The pressure applied by the absorbent material  21  to the transfer substrate  200  and the micro-semiconductor chip  110  may be determined in consideration of a material of the absorbent material  21 , moving speed of the absorbent material  21 , strength of the transfer substrate  200 , and a support state of the transfer substrate  200 . By determining the pressure at which the absorbent material  21  presses the transfer substrate  200  in consideration of the material of the absorbent material  21 , the moving speed of the absorbent material  21 , the strength of the transfer substrate  200 , and the support state of the transfer substrate  200 , a phenomenon in which the micro-semiconductor chip  110  is damaged, the transfer substrate  200  is damaged, or the transfer substrate  200  is shaken by the absorbent material  21  may be prevented. 
     The absorbent material  21  may be singular, but is not limited thereto, and as shown in  FIG.  26   , a plurality of absorbent materials  21 A and  21 B may be provided. 
     According to the process of scanning the transfer substrate  200  by the absorbent material  21 , as shown in  FIG.  27   , the plurality of micro-semiconductor chips  110  are inserted and aligned in the groove h of the transfer substrate  200 . In this case, some micro-semiconductor chips  110  may be located on the surface of the transfer substrate  200  without being inserted into the groove h. The micro-semiconductor chip  110  may be referred to as a dummy micro-semiconductor chip  110 D. The liquid L may hardly remain on the transfer substrate  200  due to evaporation or absorption. In this case, the fluidity of the dummy micro-semiconductor chip  110 D may be deteriorated. 
     The cleaning module  30  may be configured to remove the dummy micro-semiconductor chip  110 D remaining on the surface of the transfer substrate  200  after alignment of the plurality of micro-semiconductor chips  110  in the plurality of grooves h by the chip alignment module  20  is completed. The cleaning module  30  may remove the dummy micro-semiconductor chip  110 D by various methods. 
     For example, referring to  FIGS.  28  and  29   , the cleaning module  30  may include a second liquid supply module  410  and a pressurization module  420 . 
     The second liquid supply module  410  may supply the liquid L on the transfer substrate  200  to increase the fluidity of the dummy micro-semiconductor chip  110 D. 
     The liquid L may be any type of liquid as long as it does not corrode or damage the micro-semiconductor chip  110 . The liquid L may be the same as the liquid L supplied by the chip supply module  330 , but is not limited thereto, and may be different. 
     The liquid L may include, for example, at least one of water, ethanol, alcohol, polyol, ketone, halocarbon, acetone, a flux, or an organic solvent. The organic solvent may include, for example, IPA. The liquid L is not limited thereto, and various changes are possible. 
     In a state in which the liquid L is supplied, the pressurization module  420  may move while contacting and pressing the surface of the transfer substrate  200 . 
     The pressure applied to the transfer substrate  200  by the pressure module  420  may be greater than the pressure applied to the transfer substrate  200  by the absorbent material  21  of the chip alignment module  20 . Through this, the dummy micro-semiconductor chip  110 D attached to the surface of the transfer substrate  200  may be easily separated in the scanning operation by the chip alignment module  20 . 
     The dummy micro-semiconductor chip  110 D may be separated from the surface of the transfer substrate  200  by the pressurization module  420  and may be transferred to the outside of the transfer substrate  200 . Accordingly, as shown in  FIG.  30   , the transfer substrate  200  may be in a state in which the plurality of micro-semiconductor chips  110  are aligned in the plurality of grooves h, and the dummy micro-semiconductor chip  110 D is removed. 
     The pressurization module  420  may be a member capable of pressing enough not to damage the dummy micro-semiconductor chip  110 D. 
     For example, the pressurization module  420  may include an absorbent material  421  that absorbs the liquid L. The absorbent material  421  may include, for example, fabric, tissue, polyester fiber, paper, or a wiper. The absorbent material  421  may be used alone without other auxiliary devices. The pressurization module  420  may include a support  422  supporting the absorbent material  421 . For example, the support  422  may include a rod, a blade, a plate, or a wiper. The absorbent material  421  may be provided on either side of the support  422 , or may have a shape wound around the support  422 . 
     As another example, as shown in  FIG.  31   , a pressurization module  420   a  may include an elastic member  423  that is elastically deformable instead of the absorbent material  421 . For example, the elastic member  423  may include a silicone material. 
     Referring back to  FIG.  29   , in the pressure module  420 , the dummy micro-semiconductor chip  110 D may be attached to a surface of the absorbent material  421  during a cleaning process. In consideration of this point, the pressurization module  420  may have a rotatable structure. For example, the absorbent material  421  may rotate about a rotation axis. By rotating the absorbent material  421  at a certain cycle or under a certain condition, the surface of the absorbent material  421  to which the dummy micro-semiconductor chip  110 D is adhered may be turned back, and a clean surface to which the dummy micro-semiconductor chip  110 D is not attached may be located at a front end in a moving direction of the pressurization module  420 . Accordingly, contamination of the surface of the transfer substrate  200  by the pressurization module  420  may be prevented. 
     However, the configuration of the cleaning module  30  is not limited thereto, and may be variously modified. 
     For example, referring to  FIGS.  32  and  33   , the cleaning module  30  may include an adhesive member  32 . The cleaning module  30  may be configured such that the adhesive member  32  approaches and moves apart from the transfer substrate  200 . The adhesive member  32  may approach a height at which only the dummy micro-semiconductor chip  110 D contacts without contacting the surface of the transfer substrate  200 . In this process, only the dummy micro-semiconductor chip  110 D may be selectively adhered to the adhesive member  32 . Accordingly, only the dummy micro-semiconductor chip  110 D may be selectively removed from the transfer substrate  200 . 
     As another example, referring to  FIG.  34   , the cleaning module  30  may include a light irradiator  33  for irradiating pulsed light P on the transfer substrate  200 . The light irradiator  510  may be a pulse lamp. For example, the light irradiator  510  may be a Xenon lamp. As the liquid L or foreign substances expand between the surface of the transfer substrate  200  and the dummy micro-semiconductor chip  110 D by the pulsed light P provided to the transfer substrate  200 , the dummy micro-semiconductor chip  110 D may be separated from the surface of the transfer substrate  200 . 
     As another example, referring to  FIG.  35   , the cleaning module  30  may include a laser irradiator  520  for locally irradiating a laser beam L on the transfer substrate  200 . The laser irradiator  520  may locally irradiate the laser beam L between the dummy micro-semiconductor chip  110 D and the surface of the transfer substrate  200 . The laser irradiator  520  may selectively focus the laser beam L on a lower area of the dummy micro-semiconductor chip  110 D to separate the dummy micro-semiconductor chip  110 D from the surface of the transfer substrate  200 . 
     Referring to  FIGS.  18  and  36   , the chip transfer apparatus  1  according to the example embodiment may further include the inspection module  40  for inspecting a state of the transfer substrate  200 . The inspection module  40  may be a camera capable of high-resolution image analysis. The inspection module  40  may inspect the state of the transfer substrate  200  through image analysis. 
     For example, the inspection module  40  may inspect an alignment state of the micro-semiconductor chip  110  on the transfer substrate  200 . Based on a result of the inspection by the inspection module  40 , the controller  70  may control at least one of the chip transfer module  10  and the chip alignment module  20  to operate. Through this, the alignment accuracy of the plurality of micro-semiconductor chips  110  may be improved. 
     For example, the inspection result by the inspection module  40 , as shown in  FIG.  37   , a position A of the groove h in which the micro-semiconductor chip  110  is not aligned from among the plurality of grooves h of the transfer substrate  200  may be identified. In this case, based on the inspection result by the inspection module  40 , the controller  70  may control at least one of the chip transfer module  10  and the chip alignment module  20  to operate based on the identified position A of the groove h. 
     As another example, the inspection module  40  may inspect a supply state of the plurality of micro-semiconductor chips  110  and the liquid L on the transfer substrate  200 . 
     For example, the inspection module  40  may inspect whether the liquid L is present on the transfer substrate  200  or whether the liquid L is sufficient even if the liquid L is present. Based on the inspection result by the inspection module  40 , the controller  70  may control the chip supply module  330  to operate. 
     For example, the inspection module  40  may inspect whether the plurality of micro-semiconductor chips  110  exist on the transfer substrate  200  or whether the plurality of micro-semiconductor chips  110  are sufficient even if the plurality of micro-semiconductor chips  110  exist. Based on the inspection result by the inspection module  40 , the controller  70  may control the chip supply module  330  to operate. 
     As such, by controlling at least one of the chip transfer module  10  and the chip alignment module  20  to operate based on the inspection result by the inspection module  40 , the control unit  70  may improve the alignment accuracy of the plurality of micro-semiconductor chips  110 . 
       FIG.  38    is a view for explaining a configuration for supporting the transfer substrate  200  and a peripheral member thereof in a chip transfer apparatus. Referring to  FIG.  38   , the chip transfer apparatus  1  according to an example embodiment may include a substrate support  80  and a recovery module  50 . 
     The substrate support  80  may support the transfer substrate  200 . The substrate support  80  supports the transfer substrate  200  so that the transfer substrate  200  does not move unintentionally during relative movement of the absorbent material  21  and the transfer substrate  200 . The substrate support  80  may adsorb and support a lower surface of the transfer substrate  200 . The substrate support  80  may be rotatable. However, the support structure and operation of the substrate support  80  is not limited thereto, and may be variously modified. 
     The recovery module  50  may recover the dummy micro-semiconductor chip  110 D. The recovery module  50  may include an accommodating unit S 1  accommodating the dummy micro-semiconductor chip  110 D separated from the transfer substrate  200 . The dummy micro-semiconductor chip  110 D accommodated in the accommodating unit S 1  may be recycled. The recovery module  50  may have a structure in which a fluid flows toward the accommodating unit S 1  on a bottom surface  91  so that the micro-semiconductor chip  110  is transferred toward the accommodating unit  51 . The bottom surface  91  may have a shape inclined downward toward a drain port  52 . 
     Referring to  FIGS.  1 ,  39 , and  40   , the chip transfer apparatus  1  according to an example embodiment may further include the antistatic module  60  that supplies ions onto the transfer substrate  200  to remove static electricity on the transfer substrate  200 . 
     The plurality of micro-semiconductor chips  110  are very small, and accordingly, even a small amount of static electricity may cause damage or unintentional movement. In consideration of this point, the antistatic module  60  may supply ions for preventing static electricity to the transfer substrate  200  or the plurality of micro-semiconductor chips  110 . 
     For example, referring to  FIG.  39   , the antistatic module  60  may supply ions for preventing static electricity to the transfer substrate  200  before the plurality of micro-semiconductor chips  110  are supplied onto the transfer substrate  200 . As another example, referring to  FIG.  40   , the antistatic module  60  may supply ions for preventing static electricity after the plurality of micro-semiconductor chips  110  are supplied onto the transfer substrate  200  and alignment of the plurality of micro-semiconductor chips  110  is progressed to some extent. 
     An electronic device may be manufactured using the wet-transferred micro-semiconductor chip  110 . When the micro-semiconductor chip  110  is a light-emitting diode, a display device may be manufactured using the wet-transferred micro-semiconductor chip  110 . 
     A chip transfer apparatus according to an example embodiment may efficiently align micro-semiconductor chips on a large area by a wet method. Because the micro-semiconductor chip may be quickly transferred to a large area, the micro-semiconductor chip may be applied to a large display device, and the cost of transferring the micro-semiconductor chip to a large area may be lowered to lower the unit cost of a display device. 
     It should be understood that example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other example embodiments. While one or more example embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.