Abstract:
A semiconductor chip transferring method and apparatus is described having a movable member, a flexible structure having adhesive on a lower surface thereof, a first transport assembly, and a second transport assembly. The first transport assembly is positioned beneath the support structure and includes a rotatable base upon which is mounted at least one arm. The movable member is extended into and flexes the support structure to transfer a semiconductor chip supported on a first side by the support structure to the arm which supports it on a second side. The first transport assembly moves the chip to the second transport assembly which may, in turn, move it to an output container which supports the second side. The chip has now been inverted from its initial orientation.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an apparatus and method for use in chip processing. More particularly, the present invention relates to an apparatus and method for efficiently and safely transferring semiconductor chips from an input location to an output location. 
     BACKGROUND OF THE INVENTION 
     Semiconductor chips are routinely manufactured and coated in one or more locations and then transferred to transportation structures for transport to a distant location for incorporation into electronic packages or devices. Semiconductor chips are formed from wafers. If the semiconductor chips are laser emitters, the completed wafers are scribed and broken into laser bars. The edges of the laser bars are then coated with a dielectric, semi-reflective coating, usually accomplished in an evaporator. The coated bars are then unloaded into waffle packs or onto an adhesive tape. The bars are then electrically tested and then reloaded into the waffle packs or onto the tape. Then the bars are scribed and broken into individual chips. The chips are then placed on an adhesive tape for inspection in an inspection machine, usually with the p contact side facing up. Generally, the adhesive tape is mounted on a supporting hoop. 
     The hoop is mounted, with the p-contact side of the chips facing up, in a pick and place machine. The pick and place machine is indexed to the first chip. The p-contact side of that chip is inspected on the hoop by an overhead camera looking downwardly. A vacuum collet then picks up the chip and moves it over an upwardly looking camera to inspect the n-contact side. Good chips, namely those chips that pass these two visual inspections of the n- and p-contact sides, are placed in a waffle pack with the p-contact side facing up. 
     Generally, chips are processed with the p contact facing up. Oftentimes, customers of such chips have a bonding orientation which is p contact down. Thus, each of the chips must be flipped over. It is impractical to flip each chip individually. As noted above, pick and place equipment lodges the chips in a waffle pack. To flip the chips, a second waffle pack is placed in a mirror relationship with the first waffle pack and the waffle packs are flipped to obtain the proper orientation, as shown in FIGS. 12-15. 
     Specifically, as shown in FIG. 12, a waffle pack  100 , having a top side  102  and a bottom side  104 , includes a plurality of recessed portions into which chips  40  are placed. The chips  40  have a p contact side  42  and an n contact side  44 , and are placed in the recessed portions with the p contact side  42  facing upwardly. A second waffle pack  110 , having a top side  112  and a bottom side  114 , is positioned over the first waffle pack  100  (FIG. 13) such that the top sides  102 ,  112  face one another. A piece of adhesive  120  may be placed between the waffle packs  100 ,  110 . 
     A vacuum may be introduced to the waffle pack  100  in the direction of arrows J. The vacuum creates a pulling force on the adhesive  120  such that the surface  122  of the adhesive  120  comes in contact with and adheres to the semiconductor chips  40 . With reference to FIG. 14, after the vacuum has caused the chips  40  to adhere to the adhesive  120 , the second carrier  110  is moved away from the carrier  100  in the direction of arrows H. With reference to FIG. 15, the second carrier  110  is re-inverted such that the semiconductor chips  40  are positioned above the surface  122  of the adhesive  120  with the n contact side  44  up. 
     Alternatively, the waffle packs  100 ,  110  without the interspersed adhesive  120  can be flipped, thereby causing the chips  40  to move by gravity into residence in the recessed portions of the waffle pack  110  with the n contact side  44  up. 
     Waffle pack flipping has deficiencies, including spillage of chips and the need for additional manipulation of the chips within the waffle pack, such as, for example, with tweezers or sharpened prods. 
     SUMMARY OF THE INVENTION 
     The present invention addresses and overcomes the above-noted deficiencies by providing a semiconductor chip transferring apparatus having a movable element, a support structure having adhesive on a lower surface thereof, and first and second transport assemblies. The first transport assembly is positioned beneath the support structure and has at least one arm rotatable around a first axis. The movable element moves at least part of the support structure containing a chip to transfer the chip to the arm. The second transport assembly is in rotatable connection with the first transport assembly and has at least one arm extending downwardly and rotatable around a second axis. The first transport assembly rotates a chip transferred from the support structure to the second transport assembly which, in turn, transports it to an output container. 
     The present invention further overcomes the deficiencies found in known methodologies by providing a method of transferring semiconductor chips. The method includes the steps of moving a transfer element into contact with a first side of a flexible film having at least one semiconductor chip adhered to a second side of said flexible film. The transfer element flexes the film and moves the chip. Further, the moved chip is received from the film on a first transport assembly and transferred to a second transport assembly which transfers the chip to an output container. 
     The method and apparatus, in transferring and transporting the chip causes a first side which is supported by the support structure and a second side which is unsupported to be placed in the container with the first side unsupported and the second side supported by the container. 
     These and other features and advantages of the invention will be more clearly understood from the following detailed description of the invention which is provided in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a semiconductor chip transferring apparatus showing an ejector assembly in cross-section constructed in accordance with an embodiment of the present invention. 
     FIG. 2 is a perspective view of the ejector assembly of FIG.  1 . 
     FIG. 3 is a view from the top of the assembly of FIG.  1 . 
     FIG. 4 is a cross-sectional view along line III—III of the ejector assembly of FIG.  2 . 
     FIG. 5 is a view from the side of the hoop of FIG.  1 . 
     FIG. 6 is a view from the top of the hoop of FIG.  1 . 
     FIG. 7 is a view from the top of the swing arm assembly of FIG.  1 . 
     FIG. 8 is a cross-sectional view along line VII—VII of the swing arm assembly of FIG.  7 . 
     FIG. 9 is a view from the top of the handler pickup tool of FIG.  1 . 
     FIG. 10 is a cross-sectional view along line IX—IX of the handler pickup tool of FIG.  9 . 
     FIG. 11 is a partial view from the top of the output pack of FIG.  1 . 
     FIG. 12 is a cross-sectional view of a known waffle pack. 
     FIG. 13 is a cross-sectional view of a pair of waffle packs in a mirrored relationship. 
     FIG. 14 is a cross-sectional view showing the movement of the second waffle pack from the first waffle pack of FIG.  13 . 
     FIG. 15 is a cross-sectional view of the second waffle pack of FIG.  13 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1-4 illustrate an embodiment of the invention. As shown therein, an ejector assembly  10  is provided which includes an anvil  12  and a piston  14 . The anvil  12  includes a plurality of openings  20  (FIG. 4) which extend from a lower surface  19  to a side surface  21 . 
     The piston  14  extends through an opening  18  creating an annular space into which a seal  22  fits. An end  16  of the piston  14  is rounded. Alternatively, the end  16  may have a different shape, such as, for example, a shape having a reduced diameter as compared with the remainder of the piston  14 . The piston  14  is extended through the opening  18  to push against and elastically deform a tape  34  supported by the hoop  30  (described in detail below). The tape  34  has an adhesive surface to which a plurality of chips  40  are adhered. 
     The hoop  30 , which is shown in greater detail in FIGS. 5-6, includes a hoop frame  32  surrounding the periphery thereof. A tape  34  extends across the hoop  30  and is affixed to a surface  33  of the hoop frame  32 . The tape  34  has an adhesive side facing away from the surface  33 . Further, the tape  34  is affixed to the surface  33  by way of an adhesive strip corresponding to the circular profile of the hoop frame  32  and positioned on the side of the tape  34  facing toward the surface  33 , or alternatively, by way of a separate adhering structure. The separate adhering structure could include clamps, clips, or a layer of glue or other adherent being located on the tape  34  or surface of the hoop frame  32 . The adhering side of the tape  34  is used for adhering semiconductor chips  40 , although other similar objects may be so adhered. 
     The hoop  30  is used for providing a stable mounting structure for the chips  40  during transportation from an input location, such as the point of manufacture, to an output location (described in detail below). As shown, the chips  40  are oriented such that the p contact side  42  is away from the tape  34  and facing downwardly. 
     Returning to FIG. 1, a chip  40  mounted on the tape  34  is removed from the tape  34  by the piston  14 . When actuated, the piston  14  pushes into the back side of the tape  34  to move the tape  34 , and the chip  40  positioned at the location on the tape  34  corresponding to the location of the piston  14 , out of a plane containing the remaining chips  40  and towards and onto an arm  52  of a first transport assembly  50 . 
     FIGS. 1,  7 - 8  show the first transport assembly  50  used to transfer the chips  40  from the hoop  30  to the second transport assembly  60  (FIGS. 9-10, to be described in detail below). The first transport assembly  50  includes a pair of arms  52  mounted on a base  54 . The base  54  is itself mounted on a rotatable leg  56 . As illustrated in FIGS. 1,  8 , the leg  56  rotates about an axis in a direction of the arrow B, although it is understood that the leg  56  may rotate in a direction opposite the arrow B. A vacuum opening  58  is located at an end  53  of the arms  52 . A vacuum is exerted by way of a pump  55  (shown schematically in FIG. 8) or other suitable device providing a force through the openings  58  in a direction of the arrow E. 
     By the rotation of the leg  56 , the arm  52  is swung toward the second transport assembly  60 , shown in FIGS. 1,  9 - 10 . The second transport assembly  60 , which is utilized to transfer the chips  40  from the first transport assembly  50  to an output location, includes a pair of downwardly extending pickup tools  62  mounted upon a base  66 . The base  66  is mounted on a rotatable arm  68 . The arm  68  rotates about an axis in a direction of the arrow C, although it is understood that the arm  68  may rotate in a direction opposite the arrow C. An opening  64  is located at an end  63  of the tools  62 , through which a vacuum is exerted by way of a pump  65  (shown schematically in FIG.  10 ), or other suitable device. This vacuum assists in maintaining the mounting of the chip  40  on the end  63  of the tool  62  during transfer to the output location, namely an output container  70 . 
     The output container  70  includes a base  72  and a plurality of output locations  73  on the base  72  for placing one or more semiconductor chips  40  (FIGS. 1,  11 ). The locations  73  may be along a top plane of the base  72 , or alternatively, the locations  73  may include recessed portions of the container  70 . 
     In operation, the anvil  12  and the piston  14  are used to dismount the chips  40  from the hoop  30 . The remaining structures in FIG. 1, namely the first transport assembly  50  and the second transport assembly  60  are utilized to transport the chips  40  to the output container  70 . 
     As shown in FIG. 1, a vacuum is pulled, by way of a pump  25  (shown schematically) or other suitable device, through the openings  20 , thereby creating a force in the direction of the arrows A away from the hoop  30 . This force keeps the hoop  30  in place while the semiconductor chips  40  are transferred to the first transport assembly  50 . Further, the force prevents the tape  34  from sagging due to the force of gravity. The seal  22  prevents leakage of the vacuum through the opening  18 , allowing the vacuum to be directed through the openings  20 . 
     As shown in FIG. 1, the piston  14  is pushed into the tape  34  at a location directly above a semiconductor chip  40 . The adhering side of the tape  34  faces downwardly. One of the swing arms  52  is positioned directly beneath the semiconductor chip  40  adhered to the tape  34 . The piston  14  pushes down on the tape  43  directly above the chip  40 , pushing the chip  40  toward the vacuum opening  58  on the end  53  of one arm  52 . The rounded end  16  of the piston  14  causes portions of the chip  40  to become loosened from the tape  34  as a chip  40  is transferred to the swing arm  52 . During this transfer, the piston  14  is retracted to its original position. 
     The force in the direction of the arrow E from the vacuum from the pump  55  pulled through the opening  58  combines with the retraction of the piston  14  to transfer the chip  40  from the hoop  30  to the swing arm  52 . Once the chip  40  has been transferred to the swing arm  52 , the hoop  30  may be reoriented under the anvil  12  to place another chip  40  beneath the piston  14 . The force from the vacuum keeps the chip  40  mounted on the end  53  of the arm  52  while the leg  56  rotates in the direction of arrow B, thereby swinging the arm  52  with the chip  40  away from the hoop  30 . 
     The arm  52  with the chip  40  is swung underneath one of the tools  62  of the second transport assembly  60 . A vacuum is exerted from the pump  65  through the opening  64  onto the chip  40 . The vacuum pulled in the direction of arrow F creates a force through the opening  64  which may be greater than the force of the vacuum being pulled in the direction E through the opening  58  in the arm  52 . Alternatively, the vacuum exerted through the opening  58  may be shut off. Either way, the chip  40  is transferred from the arm  52  to the tool  62 . 
     In an alternative embodiment, the ends  63  may include adhesive properties similar to the adhesive properties on the adhesive side of the hoop  30 . The adhesive properties on the ends  63  may be greater than the vacuum being exerted in the direction of arrow E through the arms  52 , or the vacuum through the arms  52  may be shut off, allowing the chip to be transferred to the end  63  of the arm  62 . 
     Once the chip  40  is secured to the tool  62 , either via vacuum or adhesive, or both, the rotatable arm  68  is rotated in a direction of arrow C. The tool  62  is rotated to a position above the output container  70 . The vacuum being exerted from the pump  65  through the opening  64  is shut off, allowing the chip  40  to settle on an output location  73  of the output container  70 . Alternatively, as shown in FIGS. 1,  11 , for the embodiment having an adhesive on the end  63 , a vacuum may be exerted, by way of a pump  85  (shown schematically in FIG. 11) or other similar device, through an opening  75  in the locations  73  of the output container  70  in a direction of the arrow G (FIG.  1 ). The vacuum exerted in the direction G must be greater than the adherent strength of the adhesive on the end  63  for the chip to be transferred to the location  73  of the output container  70 . 
     Through the above described method and apparatus, a semiconductor chip  40 , which is adhered to the tape  34  with the p contact side up, is delivered to the output container  70  with the p contact side down. When on the tape  34 , the p contact side of the chip  40  is unsupported, while the n contact side is supported by the tape  34 . Upon transfer of the chip  40  to the first transport assembly  50 , the p contact side is supported by one of the swing arms  52 . One of the pickup tools  62  supports the n contact side of the chip  40  upon its transfer to the second transport assembly  60 . And, upon final transport to the output container  70 , the p contact side of the chip  40  is supported in the location  73 . 
     It is possible to transfer one semiconductor chip  40  from the swing arm assembly  50  to the second transport assembly  60  while transferring another chip  40  from the anvil  12  to the swing arm assembly  50 . Further, a chip  40  may be transferred from the second transport assembly  60  to the output container  70  while another chip  40  is transferred from the swing arm assembly  50  to the second transport assembly  60 . 
     In the above described embodiments, a plurality of semiconductor chips can be efficiently transferred from a processing unit to a transporting container with proper orientation and with a reduced likelihood of damage to the chips. 
     While the invention has been described in detail in connection with the preferred embodiments known at the time, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.