Abstract:
A light-emitting diode (LED) wafer picker that may increase a suction force and may perform stable adsorption without a concern for contact with a top surface of an LED wafer is provided. An LED wafer picker may include a main body to hold, in an adsorbed state, an LED wafer disposed below the main body, when air drawn in from a top of the LED wafer picker is discharged along a streamlined discharge surface to both sides of the LED wafer picker, a guide member to enable the air to flow along the discharge surface, the guide member being disposed below the discharge surface, a single central hole formed in a central portion of the guide member, excluding a portion facing the discharge surface, and a support portion to support the LED wafer, the support portion extending downward from the guide member. Accordingly, it is possible to easily perform adsorption of an LED wafer that is relatively far from the LED wafer picker. Additionally, it is possible to prevent the top surface of the LED wafer from coming into contact with the guide member, thereby reducing detects due to contamination of foreign substances.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a light-emitting diode (LED) wafer picker, and more particularly, to an LED wafer picker for holding an LED wafer in an adsorbed state using air without being in contact with the LED wafer, to transfer the LED wafer. 
       BACKGROUND 
       [0002]    In general, sapphire wafers are used to manufacture light-emitting diodes (LEDs) and the like. To transfer such an LED wafer, a picker to pick up the LED wafer may be used. 
         [0003]    A conventional LED wafer picker creates predetermined vacuum by drawing air, and fixes an LED wafer. However, since such a vacuum adsorption scheme enables the LED wafer to come into direct contact with an adsorption pad, foreign substances attached to the adsorption pad may contaminate a surface of the LED wafer, or damage the LED wafer. 
         [0004]    To solve the above problems, a non-contact type LED wafer picker may be used. The non-contact type LED wafer picker may not come into contact with the surface of the LED wafer, based on the Bernoulli&#39;s principle. A conventional non-contact type LED wafer picker may enable compressed air to quickly flow along a streamlined discharge surface, so that an LED wafer may be held in an adsorbed state at a predetermined distance from the discharge surface. 
         [0005]      FIG. 1  is a diagram illustrating a cross section of a conventional LED wafer picker,  FIG. 2  is a diagram illustrating a bottom of the conventional LED wafer picker, and  FIG. 3  is a diagram illustrating an example of an operation of the conventional LED wafer picker. 
         [0006]    In  FIGS. 1 through 3 , the conventional LED wafer picker may include a main body  110 , and a guide member  120 . 
         [0007]    The main body  110  may have a structure in which air is drawn in from a top of the main body  110  and is discharged toward a bottom of the main body  110 . In this instance, the air may flow out to both sides along a streamlined discharge surface  111  in the bottom of the main body  110 . 
         [0008]    The guide member  120  may be disposed below the discharge surface  111 , and may guide the air so that the air may flow along the discharge surface  111 . The guide member  120  may include a plurality of fine holes  121  through which air flows. 
         [0009]    Specifically, since highly compressed air drawn in from the top of the main body  110  may quickly flow along the streamlined discharge surface  111 , a central portion of the discharge surface  111  may be temporally maintained in a vacuum state. Accordingly, negative pressure may be generated in an upward direction from the bottom of the main body  110 , so that an LED wafer  199  ( FIG. 3 ) disposed below the main body  110  may be held in an adsorbed state through the fine holes  121  of the guide member  120 . 
         [0010]    However, in the conventional LED wafer picker, a suction force required to adsorb the LED wafer  199  is reduced due to the fine holes  121  of the guide member  120 . 
         [0011]    Additionally, when the LED wafer  199  is held in the adsorbed state, there is concern that a top surface of the LED wafer  199  may come into contact with the guide member  120 . When the top surface of the LED wafer  199  comes into contact with the guide member  120 , various foreign substances may be attached to the top surface of the LED wafer  199  and, accordingly, defects may occur. 
       SUMMARY 
       [0012]    An aspect of the present invention provides a light-emitting diode (LED) wafer picker that increases a suction force and performs stable adsorption without a concern for contact with a top surface of an LED wafer. 
         [0013]    According to an aspect of the present invention, there is provided an LED wafer picker including: a main body to hold, in an adsorbed state, an LED wafer disposed below the main body, when air drawn in from a top of the LED wafer picker is discharged along a streamlined discharge surface to both sides of the LED wafer picker; a guide member to enable the air to flow along the discharge surface, the guide member being disposed below the discharge surface; a single central hole formed in a central portion of the guide member, excluding a portion facing the discharge surface; and a support portion to support the LED wafer, the support portion extending downward from the guide member. 
         [0014]    An inclined taper may be formed in a lower end of the support portion to have a gradually decreasing diameter toward the lower end of the support portion. 
         [0015]    The main body may include a sensor hole that is formed in the main body within a range of a diameter of the central hole and into which a sensor is inserted. 
         [0016]    According to another aspect of the present invention, there is provided an LED wafer picker including: a main body to hold, in an adsorbed state, an LED wafer disposed below the main body, when air drawn in from a top of the LED wafer picker is discharged along a streamlined discharge surface to both sides of the LED wafer picker; a guide member to enable the air to flow along the discharge surface, the guide member being disposed below the discharge surface; a single central hole formed in a central portion of the guide member, excluding a portion facing the discharge surface; and a support portion to support the LED wafer, the support portion extending laterally from the guide member. 
         [0017]    An inclined taper may be formed in the support portion to have a gradually decreasing diameter toward a lower end of the support portion. 
         [0018]    The guide member may be integrally coupled to the main body. 
         [0019]    According to embodiments of the present invention, a light-emitting diode (LED) wafer picker may increase a suction force due to a central hole formed in a guide member and accordingly, may easily perform adsorption of an LED wafer that is relatively far from the LED wafer picker. 
         [0020]    Additionally, according to embodiments of the present invention, in an LED wafer picker, a support portion may be formed in a guide member, and a taper may be formed in the support portion, and thus it is possible to prevent a top surface of an LED wafer from coming into contact with the guide member, thereby reducing detects due to contamination of foreign substances. 
         [0021]    Furthermore, according to embodiments of the present invention, an LED wafer picker may be formed integrally with a guide member, and thus it is possible to reduce costs and a total quantity of parts, and possible to facilitate maintenance due to a simple structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    These and/or other aspects, features, and advantages of the invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings of which: 
           [0023]      FIG. 1  is a diagram illustrating a cross section of a conventional prior-art light-emitting diode (LED) wafer picker; 
           [0024]      FIG. 2  is a diagram illustrating a bottom of the conventional prior-art LED wafer picker; 
           [0025]      FIG. 3  is a diagram illustrating an example of an operation of the conventional prior-art LED wafer picker; 
           [0026]      FIG. 4  is a diagram illustrating a cross section of an LED wafer picker according to an embodiment of the present invention; 
           [0027]      FIG. 5  is a diagram illustrating a bottom of the LED wafer picker of  FIG. 4 ; 
           [0028]      FIG. 6  is a diagram illustrating an example of an operation of the LED wafer picker of  FIG. 4 ; 
           [0029]      FIG. 7  is a diagram illustrating an enlarged support portion of the LED wafer picker of  FIG. 4 ; 
           [0030]      FIG. 8  is a diagram illustrating a cross section of an LED wafer picker according to another embodiment of the present invention; 
           [0031]      FIG. 9  is a diagram illustrating a bottom of the LED wafer picker of  FIG. 8 ; 
           [0032]      FIG. 10  is a diagram illustrating an example of an operation of the LED wafer picker of  FIG. 8 ; and 
           [0033]      FIG. 11  is a diagram illustrating an enlarged support portion of the LED wafer picker of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Exemplary embodiments are described below to explain the present invention by referring to the figures. 
         [0035]    Hereinafter, a technical configuration of a light-emitting diode (LED) wafer picker will be described in detail based on the accompanying drawings. 
         [0036]      FIG. 4  is a diagram illustrating a cross section of an LED wafer picker according to an embodiment of the present invention, and  FIG. 5  is a diagram illustrating a bottom of the LED wafer picker of  FIG. 4 .  FIG. 6  is a diagram illustrating an example of an operation of the LED wafer picker of  FIG. 4 , and  FIG. 7  is a diagram illustrating an enlarged support portion of the LED wafer picker of  FIG. 4 . 
         [0037]    In  FIGS. 4 through 7 , the LED wafer picker may include a main body  10 , and a guide member  20 . 
         [0038]    The main body  10  may hold, in an adsorbed state, an LED wafer  99  disposed below the main body, when air drawn in from a top of the main body  10  is discharged along a streamlined discharge surface  11  to both sides of the LED wafer picker. In other words, an inlet  12  may be formed in an upper portion of the main body  10 , and may supply highly compressed air. The inlet  12  may be connected to a hose, a pipe, and the like. 
         [0039]    The guide member  20  may be disposed below the discharge surface  11 , and may guide the air so that the air may flow along the discharge surface  11 . 
         [0040]    The discharge surface  11  formed in the bottom of the main body  10  may have a streamlined cross section. The compressed air supplied via the inlet  12  may be discharged to a lower portion of the main body  10 . The discharged air may quickly flow along the streamlined discharge surface  11 , so that vacuum may be temporally created in a central portion of the main body  10 . 
         [0041]    Due to the vacuum created in the central portion of the main body  10 , negative pressure may be generated in an upward direction, namely, a direction that enables the LED wafer  99  below the main body  10  to be adsorbed toward the main body  10 . 
         [0042]    In this instance, a single central hole  25  may be formed in a central portion of the guide member  20 , excluding a portion facing the discharge surface  11 . In other words, a diameter of the central hole  25  may not exceed a circumference of the portion facing the discharge surface  11 . For example, when a picker enabling adsorbing of an LED wafer of 50 mm is used, the central hole  25  may desirably have a diameter of 40 mm. 
         [0043]    Due to the single central hole  25  formed in the central portion of the guide member  20 , a suction force may be increased by at least two-times, compared to a conventional structure in which a plurality of fine holes are formed. Thus, it is possible to easily hold, in the adsorbed state, an LED wafer that is spaced apart by a distance of 5 mm to 10 mm from a bottom of the guide member  20 . 
         [0044]    In this instance, the compressed air discharged to the lower portion of the main body  10  and flowing along the discharge surface  11  may be enabled to be discharged again toward the upper portion of the main body  10 . This is because foreign substances around the LED wafer  99  may be scattered by the compressed air flowing down toward the LED wafer  99 , and may be attached to the LED wafer  99 , which may cause defects. 
         [0045]    Additionally, the LED wafer picker of  FIG. 4  may include a support portion  30  disposed below the guide member  20 . The support portion  30  may extend downward from the guide member  20 , and may support the LED wafer  99 . 
         [0046]    The support portion  30  may have a cylindrical shape based on the center of the guide member  20 , and may correspond to a size of the LED wafer  99 , as shown in  FIG. 4 . Additionally, a plurality of support portions may be formed in a circumferential direction of the LED wafer  99 , to support the LED wafer  99  at a plurality of spots. 
         [0047]    Additionally, the main body  10  may include a sensor hole  15  into which a sensor is inserted. The sensor hole  15  may be formed in the main body  10  within a range of the diameter of the central hole  25 . 
         [0048]    As shown in  FIG. 7 , an inclined taper  31  may be formed in a lower end of the support portion  30  to have a gradually decreasing diameter toward the lower end of the support portion  30 . 
         [0049]    The LED wafer  99  may come into contact with the taper  31  and accordingly, a top surface of the LED wafer  99  may be prevented from coming into contact with the guide member  20 . Thus, it is possible to prevent a defect from occurring due to a scratch that may be caused by foreign substances attached to the top surface of the LED wafer  99 . 
         [0050]    The guide member  20  may be integrally coupled to the main body  10 . Accordingly, a total number of parts in the LED wafer picker of  FIG. 4  may be reduced, and the LED wafer picker of  FIG. 4  may be simplified, and thus it is possible to facilitate maintenance of the LED wafer picker of  FIG. 4  and to reduce manufacturing costs. 
         [0051]    In other words, in the LED wafer picker of  FIG. 4 , the suction force may be approximately doubled due to the central hole  25  formed in the central portion of the guide member  20 . Additionally, the support portion  30  including the taper  31  in a lower portion of the guide member  20  may prevent the guide member  20  from coming into contact with the top surface of the LED wafer  99 . 
         [0052]    Since the support portion  30  extends downward from the guide member  20 , the LED wafer picker of  FIG. 4  may be advantageously applied to an LED wafer with a relatively small size of about 2 inches (namely, 50 mm) 
         [0053]      FIG. 8  is a diagram illustrating a cross section of an LED wafer picker according to another embodiment of the present invention, and  FIG. 9  is a diagram illustrating a bottom of the LED wafer picker of  FIG. 8 .  FIG. 10  is a diagram illustrating an example of an operation of the LED wafer picker of  FIG. 8 , and  FIG. 11  is a diagram illustrating an enlarged support portion of the LED wafer picker of  FIG. 8 . 
         [0054]    In  FIGS. 8 through 11 , the LED wafer picker may include a main body  310 , and a guide member  320 . 
         [0055]    The main body  310  may hold, in an adsorbed state, an LED wafer  399  ( FIGS. 10 and 11 ) disposed below the main body, when an air drawn in from a top of the main body  310  is discharged along a streamlined discharge surface  311  to both sides of the LED wafer picker. In other words, an inlet  312  may be formed in an upper portion of the main body  310 , and may supply highly compressed air. The inlet  312  may be connected to a hose, a pipe, and the like. 
         [0056]    The guide member  320  may be disposed below the discharge surface  311 , and may guide the air so that the air may flow along the discharge surface  311 . 
         [0057]    The discharge surface  311  formed in the bottom of the main body  310  may have a streamlined cross section. The compressed air supplied via the inlet  312  may be discharged to a lower portion of the main body  310 . The discharged air may quickly flow along the streamlined discharge surface  311 , so that vacuum may be temporally created in a central portion of the main body  310 . 
         [0058]    Due to the vacuum created in the central portion of the main body  310 , negative pressure may be generated in an upward direction, namely, a direction that enables the LED wafer  399  below the main body  310  to be adsorbed toward the main body  310 . 
         [0059]    In this instance, a single central hole  325  may be formed in a central portion of the guide member  320 , excluding a portion facing the discharge surface  311 . In other words, a diameter of the central hole  325  may not exceed a circumference of the portion facing the discharge surface  311 . For example, when a picker enabling adsorbing of an LED wafer of 150 mm is used, the central hole  325  may desirably have a diameter of 40 mm to 60 mm, and may more desirably have a diameter of 40 mm. 
         [0060]    Due to the single central hole  325  formed in the central portion of the guide member  320 , a suction force may be increased by at least two-times, compared to a conventional structure in which a plurality of fine holes are formed. Thus, it is possible to easily hold, in the adsorbed state, an LED wafer that is spaced apart by a distance of 5 mm to 10 mm from a bottom of the guide member  320 . 
         [0061]    In this instance, the compressed air discharged to the lower portion of the main body  310  and flowing along the discharge surface  311  may be enabled to be discharged again toward the upper portion of the main body  310 . This is because foreign substances around the LED wafer  399  may be scattered by the compressed air flowing down toward the LED wafer  399 , and may be attached to the LED wafer  399 , which may cause defects. 
         [0062]    Additionally, the LED wafer picker of  FIG. 8  may include a support portion  330  disposed in a side of the guide member  320 . The support portion  330  may extend laterally from the guide member  320 , and may support the LED wafer  399 . 
         [0063]    The support portion  330  may have a cylindrical shape based on the center of the guide member  320 , and may correspond to a size of the LED wafer  399 . Additionally, as shown in  FIG. 9 , a plurality of support portions may be formed in a circumferential direction of the LED wafer  399 , to support the LED wafer  399  at a plurality of spots.  FIG. 9  illustrates four support portions  330 , but there is no limitation to a number of support portions  330 . Accordingly, the number of support portions  330  may be appropriately changed based on the size of the LED wafer  399 . 
         [0064]    Additionally, the main body  310  may include a sensor hole (not shown) into which a sensor is inserted. The sensor hole may be formed in the main body  310  within a range of the diameter of the central hole  325 . 
         [0065]    As shown in  FIG. 11 , an inclined taper  331  may be formed in the support portion  330  to have a gradually decreasing diameter toward a lower end of the support portion  330 . Additionally, the support portion  330  may include a horizontally extending portion  333 , and a bending portion  334 . The horizontally extending portion  333  may extend laterally from the guide member  320 , and the bending portion  334  may be bent downward from the horizontally extending portion  333 . The taper  331  may correspond to an inner surface of the bending portion  334 . 
         [0066]    The LED wafer  399  may come into contact with the taper  331  and accordingly, a top surface of the LED wafer  399  may be prevented from coming into contact with the guide member  320 . Thus, it is possible to prevent a defect from occurring due to a scratch that may be caused by foreign substances attached to the top surface of the LED wafer  399 . 
         [0067]    The guide member  320  may be integrally coupled to the main body  310 . Accordingly, a total number of parts in the LED wafer picker of  FIG. 8  may be reduced, and the LED wafer picker of  FIG. 8  may be simplified, and thus it is possible to facilitate maintenance of the LED wafer picker of  FIG. 8  and to reduce manufacturing costs. In this instance, the guide member  320  may include a bolt hall  329  that enables the guide member  320  to be coupled to the main body  310 . 
         [0068]    In other words, in the LED wafer picker of  FIG. 8 , the suction force may be approximately doubled due to the central hole  325  formed in the central portion of the guide member  320 . Additionally, the support portion  330  including the taper  331  ( FIG. 11 ) in a lower portion of the guide member  320  may prevent the guide member  320  from coming into contact with the top surface of the LED wafer  399 . 
         [0069]    Since the support portion  330  extends laterally from the guide member  320 , the LED wafer picker of  FIG. 8  may be advantageously applied to an LED wafer with a relatively large size of about 6 inches (namely, 150 mm). 
         [0070]    Although the LED wafer pickers according to the embodiments of the present invention have been shown and described, the present invention is not limited to the described embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.