Abstract:
The invention relates to a device for inspecting and rotating electronic components, particularly flip chips, comprising a component which is rotatably mounted at a position of rotation and which is used to rotate electric components. A first receiving element is fixed to the outer side of the component in order to receive a single electronic component of a carrier and to secure it during a rotational movement of the component. A second receiving element is arranged on the outer side of the component opposite the first receiving element in relation to the point of rotation such that when the component is rotated by 180° it respectively faces the carrier, and a through opening is arranged in the component between the receiving elements such that when the component is rotated by 90° or 270° the through opening faces the carrier. The invention relates to a method for inspecting and rotating electronic components, particularly flipchips.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional application of U.S. application Ser. No. 10/589,429, filed Nov. 3, 2006, which is a U.S. National phase application of PCT/EP2005/050388, filed Jan. 31, 2005, which claims priority to DE 10 2004 007 703.7, filed Feb. 16, 2004, the disclosure of which are hereby incorporated herein by reference in their entirety. 
     
    
     DESCRIPTION 
       [0002]    The invention relates to a device and a method for checking and rotating electronic components, in particular flip chips, with a pivoting part attached to a pivotal point for rotating the electronic components, a first pickup element being fixed on the exterior of the part for picking up a single electronic component from a substrate and keeping hold of it during a rotational movement of the part, according to the preambles of claims  1  and  7 . 
         [0003]    For methods that are based on a flip chip principle, it is known that individual electronic component parts arranged in a sandwich separated from one another, such as semiconductor chips arranged in a wafer, the wafer in turn being set on an extensible carrier sheet, are picked up from this carrier sheet and rotated, i.e. turned upside down, in order to deposit them in the rotated position for the subsequent die bond or die sort. For this purpose, the single chip is first detached from the reverse side of the carrier sheet with a needle, the so-called die ejector, and transferred with a pickup element, such as a vacuum pipette, advanced from the front or from above. For this, the vacuum pipette is usually arranged as a flip tool on a flip head of a part pivoting about a pivotal point, and keeps hold of the selected chip during a 180° rotation of the pivoting part. After the 180° rotation has taken place, the chip turned round in this way is picked up by a pick-and-place element on its reverse side, in order then to transport the chip in this rotated situation to the desired position, for example within a smart card module. 
         [0004]    In order to check the surface of the individual chip still arranged on the substrate for intactness before it is picked up, and at the same time to be able to check that it is in the correct position before it is picked up, a first optical facility, for example a camera, is arranged above the pivoting part for the inspection of the wafer. Since an optical connection line set up perpendicular to the surface of the wafer and the chip between the first optical facility and the wafer surface is important for an optimized check, the camera is arranged directly over the chip to be picked up. For this reason, the pivoting part must be rotated out of the perpendicularly running optical connection line each time before a chip is picked up, in order that a so-called wafer inspection can be performed. 
         [0005]    This results in the following sequentially occurring method sequence for each flip chip: First, a check of the surface of the chip to be picked up must be performed using the camera. The flip head is then rotated into the optical connection line, in order to pick up the chip by its upper surface using the vacuum pipette attached to the flip head. By means of the pivoting part, whose rotational axis is arranged outside the optical connection line, the chip is now rotated through 180° in such a way that the flip head is now in a rotated position outside the optical connection line. A further check performed on the chip&#39;s position by means of a second optical facility in the form of a camera should supply data on a flip offset of the flipped chip. The flipped or rotated chip is then transferred to a placing facility in the form of a place head, and a correction is made to the flip offset based on transferred correction values. 
         [0006]    Such a sequence of successive steps leads to a high time requirement for the overall process of checking and rotating a chip, and thereby reduces the throughput of the device. It therefore also results in higher operating costs. 
         [0007]    The present invention is therefore based on the object of providing a device and a method for checking and rotating electronic component parts, in particular flip chips, with a pivoting part for rotating the components, the device and the method being time- and cost-saving. This object is achieved in respect of the device in accordance with the features of claim  1 , and in respect of the method in accordance with the features of claim  7 . 
         [0008]    An essential point of the invention is that in a device for checking and rotating electronic components, such as flip chips, with a pivoting part attached to a pivotal point for rotating the electronic components, on the exterior of which part a first pickup element is fixed for taking up a single component from a substrate and keeping hold of it during a rotational movement, a second pickup element is arranged externally on the part opposite the first pickup element in relation to the pivotal point in such a way that in each case one pickup element is facing the substrate for each rotation of the part through 180°. The part further has a through opening between the pickup elements such that the through opening is facing the substrate for a rotation of the pivoting part through 90° or 270°. In this way, during a 180° rotation of the pivoting part, first the chip can be picked up from the substrate by the first pickup element, developed for example as a vacuum pipette, after a rotation through the first 90° an optical connection line between a first optical facility arranged above the pivoting part for checking the surface and the correct position of a further chip arranged on the substrate based on the vertically aligned through opening, and a depositing of the chip on a placing facility likewise arranged relocatably above the pivoting part can take place, the chip meanwhile turned round after an executed 180° rotation. At the same time, by means of the second pickup element which can likewise be developed as a vacuum pipette, the further component is picked up from the substrate, since the second pickup element is now arranged over the wafer surface. A subsequent 180° rotation in the reverse direction of the pivoting part results in a further execution of the process described above. 
         [0009]    Since a wafer inspection, a pickup and a deposit of the chip can occur within a single 180° rotation of the pivoting part developed according to the invention, as well as the turning round of the chip and also the picking up of a further chip, a considerable saving of time is hereby achieved. This considerably increases the throughput of the device as a whole, thereby reducing the operating costs of the device. 
         [0010]    According to a preferred embodiment, the first pickup element is fixed to a first projection of the part, and the second pickup element to a second projection. The through opening can then be developed between the projections as a through channel open on one of its long sides. A consequence of this that not only can the vacuum pipettes be fixed optimally to the pivoting part, but a simple manufacture of the through channel by a milling process is also possible, thus enabling economical manufacture. In addition, such a design of the pivoting part means that a rotational axis extending perpendicular to the course of the through channel is arranged not blocking the view for the first optical facility within the through channel. 
         [0011]    A second optical facility is preferably arranged in the form of a camera for checking a correct position of the previously rotated and possibly deposited chip, in order that a flip offset can be determined and correction data can accordingly be passed to the placing facility for correcting the chip&#39;s position. 
         [0012]    The first optical facility is activated with a predefinable time delay after a rotation or swivel of the through opening into the optical connection line between the first optical facility and the chip to be checked, arranged on the substrate. By this means, partially blurred images caused by the projections rotating with the part can reliably be avoided. 
         [0013]    Further advantageous embodiments will become apparent from the subclaims. 
     
    
     
         [0014]    Advantages and expediencies can be taken from the following description in conjunction with the drawing. Shown are: 
           [0015]      FIG. 1  in a schematic front view, a device for checking and rotating semiconductor chips according to prior art; 
           [0016]      FIG. 2  in a schematic front view, a device for checking and rotating semiconductor chips according to an embodiment of the present invention; 
           [0017]      FIG. 3  is also a schematic front view of the device of  FIG. 2 , with the pivoting part rotated 90 degrees. 
           [0018]      FIG. 4  is a schematic side view taken along line  4 - 4  of  FIG. 3 . 
           [0019]      FIG. 5  is the schematic view of  FIG. 4  with the pivoting part rotated 90 degrees. 
           [0020]      FIG. 6  in a perspective view, a pivoting part for the device for checking and rotating semiconductor chips according to an embodiment of the invention; 
           [0021]      FIG. 7  in a schematic side view, the pivoting part shown in FIG. [[ 3 ]]  6 ; 
           [0022]      FIG. 8  in a schematic front view, a representation of the principle of the method according to the invention; and 
           [0023]      FIG. 9  in a schematic representation, checking areas for a through opening rotated to the left and to the right within the pivoting part. 
       
    
    
       [0024]    As can be seen from  FIG. 1  in a schematic front view, previously according to prior art a pivoting part  3  was used for detaching individual semiconductor chips, not shown here, from a wafer or from its substrate  1  by means of a die ejector  2 , this part  3  enabling, by the design of a rotational axis projecting into the drawing plane to form a pivotal point  4  at the left-hand end of the part, a swivelling in and out of a flip head  5  with arranged on it a pickup element  6 , out of an optical connection line between a first optical facility  7  and the wafer surface. The solid lines of the flip head represent a pickup or pick position of the chip to be picked up, while the dotted lines of flip head  5  reflect a deposit or place position on a placing facility  8  following the pickup process. The placing facility  8  likewise has a pickup element  9 , for example in the form of a vacuum pipette, in order to place the now turned chip within a smart card module, for example, by moving the placing facility  8 . 
         [0025]    A pivoting part of this nature has only one pickup element, for one thing, and for another requires the time-consuming sequential method sequence that has already been described. 
         [0026]    In  FIG. 2 , a device for checking and rotating semiconductor chips according to an embodiment of the present invention is shown in a schematic front view. It can be seen in this representation that above a wafer and an associated substrate  11  with a wafer surface  11   a , from which individual semiconductor chips are ejected with a die ejector  12  from below upwards, a pivoting part  14  is arranged in such a way that it rotates in an executed rotation as indicated by arrows  15 ,  16  about a pivotal point  17 , which is arranged above the chip to be picked up. The wafer can be moved with the substrate  11  in the x or y direction, as is indicated by the double arrow  13 . 
         [0027]    On cheek projections  18   a  and  18   b  the pivoting part  14  has two opposite pickup elements  19 ,  20 —for example in the form of vacuum pipettes—, which enable simultaneous picking up and depositing of two semiconductor chips. The first vacuum pipette  19  can pick up a semiconductor chip from the substrate  11 , while the second vacuum pipette  20  deposits a further semiconductor chip on a placing facility  21 , which can for example be equipped with a further vacuum pipette  22 . The placing facility  21  is then moved sideways as indicated by the double arrow  24 . 
         [0028]    At almost the same time the pivoting part  14  rotates about its pivotal point  17 —this time in the opposite direction to the preceding rotation—and after a 90° rotation a through opening not shown here arranged in the pivoting part  14  generates a sight channel  23   a  from a first optical facility  23  running vertically through the part  14  to the surface  11   a  of the substrate  11  covered with the wafer to a further semiconductor chip. 
         [0029]    This sight channel is used for carrying out a short-time recording by the first optical facility  23  developed as a camera, of the further semiconductor chip to be picked up in the future on the substrate  11 , for checking of the surface and the correct position. 
         [0030]    As soon as the pivoting part  14  has finished its 180° rotation after a further 90°, the pickup of the further semiconductor chip is executed by the second vacuum pipette  20 . 
         [0031]    A second optical facility in the form of a die on the fly camera  25  is arranged for checking a flip offset of the previously rotated chip. In the event that there is a flip offset, this facility calculates corresponding correction data and passes this to the self-adjusting place element  21 . The place element  21  then deposits the chip in an indexer  26 , its position being checked by a further camera  27 . 
         [0032]      FIG. 3  shows the device of  FIG. 2 , where the pivoting part  14  is rotated 90 degrees. At this point, the placing facility  21  is moved (with a semiconductor chip) to a position over the indexer  26  and out of the optical path  23   a . The optical path  23   a  is now unobstructed as it passes between the projections  18   a ,  18   b  of the pivoting part  14  to the surface of the substrate  11   a.    
         [0033]      FIG. 4  is a side view of the device shown in  FIG. 3 . The pivoting part  14  is shown connected to the axis of the pivoting point  17  which is driven by motor  40  to rotate the pivoting part  14 . It can be seen in  FIG. 4  that the optical path  23   a  passes in front of the pivoting part  14  between the projections  18   a ,  18   b , so that the camera may view the surface of the substrate  11   a.    
         [0034]      FIG. 5  is the same view as in  FIG. 4 , except that the pivoting part  14  is rotated another 90 degrees. At the same time, placing facility  21  is returned to a position to pick up a semiconductor chip from the pickup element  19 , thereby again blocking the optical path  23   a.    
         [0035]      FIG. 6  shows in a perspective view a possible embodiment of a pivoting part  14  for its arrangement in a device according to the invention for checking and rotating electronic components. As can be seen from the representation, the pivoting part is equipped at its pivotal point  17  with a hole to accommodate a rotational axis, not shown here, around which the pivoting part  14  rotates. 
         [0036]    The projections  18   a  and  18   b  developed as cheeks are used to accommodate and attach pickup elements, not shown here, which can be developed as vacuum pipettes, for example. 
         [0037]    The through opening  28  is developed in this case as a through channel open on one long side, and milled into the part in a simple manner. 
         [0038]    As can be seen from a side view of the pivoting part in  FIG. 7 , during its rotation around a rotational axis arranged in a drilled hole  29  the part  14  permits a maximum inspection window of a distance between the projections  18   a  and  18   b.    
         [0039]    This distance can have a dimension of about 20 mm, for example. In a further rotation beyond the 90° setting of the pivoting part  14 , the inspection window then shrinks again, and vanishes entirely at a 180° setting of the pivoting part  14 . 
         [0040]      FIG. 8  shows in a simple schematic front view the functioning of the device according to the invention. The pivoting part, not shown here in detail, which is arranged between the camera  23  and the substrate  11 , contains among other features the through opening  28 , which moves in a circuit  15   a.    
         [0041]    As soon as the through opening  28  is in a vertical position, meaning that the pickup elements not shown here are aligned horizontally, the optical connection line  23   a  can be set up from the camera  23  to the semiconductor chip to be removed on the substrate  11 . Within this brief swivelling in of the through opening  28  into the optical connection line  23   a , a short-time recording takes place of the surface and the position of the semiconductor chip to be removed. A further rotation of the part in a counter-clockwise direction, as indicated by the arrow  15 , allows the pickup element not shown here to sweep to the chip to be removed and pick it up. A 180° rotation of the part then takes place in the opposite direction, i.e. clockwise as indicated by the arrow  16 . Alternatively, the pivoting part may complete a 360° rotation rather than reciprocating. 
         [0042]    In  FIG. 9  there is a schematic representation of the observation/inspection areas that are available to the camera  23  during a rotation of the part  14  developed with the through opening  28 . For a total 360° rotation of the part and the through opening counter-clockwise (reference label  31 ) and clockwise (reference label  32 ), as also indicated by arrows  33  and  34 , available inspection areas  35  and  36  are formed at an approximate 90° setting of the part. 
         [0043]    In order not to cause any blurred images in swivelling the through opening into the optical connection line between the camera and the wafer, the camera is activated with a time delay of about 10 msec, as represented by the angle sections  37  and  38 . 
         [0044]    All features disclosed in the application documents are claimed as essential for the invention, provided they are novel individually or in combination in the light of the prior art. All features disclosed in the application documents are regarded individually or in combination as essential for the invention. Variations of these are familiar to the person skilled in the art. 
       REFERENCE LABEL LIST 
       [0000]    
       
           1 ,  11  Substrate 
           2 ,  12  Die ejector 
           3  Pivoting part 
           4 ,  17  Pivotal point 
           5  Flip head 
           6  Pickup element 
           7 ,  23  Wafer optics camera 
           8  Placing facility 
           9  Pickup element 
           11   a  Surface of the substrate 
           13  Direction of movement of the substrate 
           14  Pivoting part 
           15 ,  15   a ,  16  Rotational movement 
           18   a ,  18   b  First and second projections 
           19  First pickup element 
           20  Second pickup element 
           21  Placing facility 
           22  Vacuum pipette 
           23  Camera 
           23   a  Optical connection line 
           24  Direction of movement of the placing facility 
           25  Die on the fly camera 
           26  Indexer 
           27  Place optics camera 
           28  Through channel 
           29  Drilled hole 
           30  Maximum size of the inspection window 
           31 ,  32  Total rotation of the part 
           33 ,  34  Directions of rotation 
           35 ,  36  Inspection areas 
           37 ,  38  Angle sections 
           39  Semiconductor chip 
           40  Motor