Abstract:
A method of sorting automated tray transfer trays includes detecting if a die remains in the tray. The method includes the ability to interrupt the automated tray transfer process to prevent mixing processed and unprocessed dice. An apparatus includes a sensor for detecting if a die remains in the tray. A sensor includes a protrusion on an automated tray transfer handler.

Description:
TECHNICAL FIELD 
   Disclosed embodiments relate to an automated tray transfer (ATT) tray handler. More particularly, disclosed embodiments relate to a detection system that interrupts the ATT process if a die has been left in a die pocket of a tray. 
   BACKGROUND INFORMATION 
   During testing of microelectronic dice, the dice are moved by pick-and-place mechanisms and advanced to further processing. A plurality of dice is often tested in a die tray that includes several die pockets. After testing, the die tray is removed and stacked for further use with dice that are up-line from testing. Occasionally, a die is not removed from a die pocket of a die tray, and tested devices are stacked on top of untested devices, which can result in “escapees” of untested devices. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order to understand the manner in which embodiments are obtained, a more particular description of various embodiments briefly described above will be rendered by reference to the appended drawings. Understanding that these drawings depict only typical embodiments that are not necessarily drawn to scale and are not therefore to be considered to be limiting of its scope, some embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
       FIG. 1A  is a side elevation of an automated tray transfer (ATT) mechanism and a die tray, according to an embodiment; 
       FIG. 1B  is a side cross section of the ATT mechanism depicted in  FIG. 1A  during further processing, according to an embodiment; 
       FIG. 2  is an elevational cross section of an ATT mechanism during processing, according to an embodiment; 
       FIG. 3  is a plan of a die with keep off zones (KOZs) and probe landing zones (PLZs), depicted according to an embodiment; 
       FIG. 4  is a perspective elevation of an ATT mechanism during processing with a die tray, according to an embodiment; 
       FIG. 5  is a perspective elevation of the ATT mechanism depicted in  FIG. 4  with the ATT mechanism inverted; 
       FIG. 6  is a method flow decision diagram according to various embodiments; and 
       FIG. 7  is a schematic depiction of an ATT system, according to an embodiment. 
   

   DETAILED DESCRIPTION 
   The following description includes terms, such as upper, lower, first, second, etc. that are used for descriptive purposes only and are not to be construed as limiting. The embodiments of a device or article described herein can be manufactured, used, or shipped in a number of positions and orientations. The terms “microelectronic device,” “die,” and “processor” generally refer to the physical object that is the basic workpiece that is transformed by various process operations into the desired integrated circuit device. A die is usually singulated from a wafer, and wafers may be made of semiconducting, non-semiconducting, or combinations of semiconducting and non-semiconducting materials. A board is typically a resin-impregnated fiberglass structure that acts as a mounting substrate for the die. 
   Reference will now be made to the drawings wherein like structures will usually be provided with like reference designations. In order to show the structure and process embodiments most clearly, the drawings included herein are diagrammatic representations of embodiments. Thus, the actual appearance of the fabricated structures, for example in a photomicrograph, may appear different while still incorporating the essential structures of embodiments. Moreover, the drawings show only the structures necessary to understand the embodiments. Additional structures known in the art have not been included to maintain the clarity of the drawings. 
     FIG. 1A  is a side elevation of an automated tray transfer (ATT) mechanism  100  (also referred to as a “pickup head”) and a die tray (also referred to as a “parts tray”), according to an embodiment. The ATT mechanism  100  includes a suction device  110  that is connectable to a pneumatic system. A spacer foot  112  is disposed between a top header bar  114  and a bottom foot bar  116 . A plurality of probes  118  is disposed through the bottom foot bar  116  in preparation for determining whether an obstruction such as an unremoved die has been encountered. In an embodiment, each of the plurality of probes  118  is referred to as a sensor. In an embodiment, each of the plurality of probes  118  is replaced by an optical sensor. In an embodiment, each of the plurality of probes  118  is referred to as a mechanical sensor. 
   In addition to the ATT mechanism  100 , a die tray  120  can be provided such that the ATT mechanism  100  is moved toward to the die tray  120 . The ATT mechanism is alternatively referred to as a tray handler  100 . A plurality of die pockets  122  is disposed within the die tray  120 . 
   As the ATT mechanism  100  is moved toward the die tray  120 , at least one protrusion such as a plurality of probe tips  124 , each connected with a corresponding probe of the plurality of probes  118 , is aligned to extend into the die pockets  122 . In an embodiment, the each sensor includes a probe  118  and a probe tip  124 .  FIG. 1A  depicts a residual die  126  that is an obstruction because it has not been removed from the die tray  120 . 
     FIG. 1B  is a side cross section of the ATT mechanism depicted in  FIG. 1A  during further processing, according to an embodiment. A given die pocket  122  of the die tray  120  depicts a residual die  126  such that the probe tip  124  of the probe  118  encounters the residual die  126  as an obstruction. According to an embodiment, where the probe tip  124  is immovable, a process jam occurs and an operator may be alerted in order to remove the residual die  126  such that it does not get mixed with dice that have a different test status from the residual die  126 . 
     FIG. 2  is an elevational cross section of an ATT mechanism  200  during processing, according to an embodiment. The ATT mechanism  200  includes a suction device  210  that is connectable to a pneumatic system. A spacer foot  212  is disposed between a top header bar  214  and a bottom foot bar  216 . A plurality of probes  218  are disposed through the bottom foot bar  216  in preparation for determining whether an obstruction such as an unremoved die has been encountered. 
   In addition to the ATT mechanism  100 , a die tray  220  can be provided such that the ATT mechanism  100  is moved toward to the die tray  220 . A plurality of die pockets  222  is disposed within the die tray  220 . As the ATT mechanism  200  is moved toward the die tray  220 , a plurality of probe tips  224 , each connected with a corresponding the probes  218 , is aligned to extend into the die pockets  222 .  FIG. 1A  depicts a residual die  226  that has not been removed from the die tray  220 . 
   In an embodiment where any of the probe tips  224  is sensitive such that it is movable, the residual die  226  and the site of its location in the die tray  220  within a given die pocket  222 , is memorialized such as by an automated write statement to a database, such that detection of the obstruction is done by automation. Accordingly, a given probe tip  224 ′ that encounters an obstruction that is the residual die  226 , is distinguishable from the plurality of probe tips  224  that extend into respective die pockets  222  and that do not encounter obstructions. 
   According to an embodiment, if the probe is optionally not used to memorialize the die-pocket site, a process jam occurs and an operator may be alerted in order to remove the residual die  226 . 
   Where the die-pocket site can be memorialized, according to an embodiment, and where the residual die  226  was part of a die lot that has already met the sample test criteria for this stage of the process, the process may continue by moving the die tray  220  with the ATT mechanism  200  by use of the suction device  210 . 
   Where the sample test criteria for the residual die  226  has not been met, a process jam occurs and an operator may be alerted to remove the residual die  226 . 
     FIG. 3  is a plan of a residual die  326  with keep off zones (KOZs)  328  and probe landing zones (PLZs)  330 , depicted according to an embodiment. A KOZ is a region on a die surface that is to avoid any contact with a probe, which could damage the die in this region. A PLZ is a region on a die that can sustain a test probe touching it, which allows for probe testing of the die. Because each die has specific KOZs  328 , it is useful to have the probe tip encounter the die in regions other than the KOZs  328 . The residual die  326  depicts a probe tip landing pad  330  that allows for the probe tip to encounter the residual die  326  when it is an obstruction that is left within a die tray. 
     FIG. 4  is a perspective elevation of an ATT mechanism  400  during processing with a die tray  420 , according to an embodiment. The ATT mechanism  400  includes a suction device  410  that is connectable to a pneumatic system. A spacer foot  412  is disposed between a top header bar  414  and a bottom foot bar  416 . A plurality of probes  418  are disposed through the bottom foot bar  416  in preparation for determining whether an obstruction such as an unremoved die has been encountered. 
   In an embodiment in addition to the ATT mechanism  400 , a die tray  420  is provided such that the ATT mechanism  400  is moved toward to the die tray  420 . A plurality of die pockets  422  is disposed within the die tray  420 . As the ATT mechanism  400  is moved toward the die tray  420 , a plurality of probe tips  424  (see  FIG. 5 ), each connected with the probes  418 , is aligned to extend into the die pockets  422 .  FIG. 1A  depicts a residual die  426  that has not been removed from the die tray  420 . 
     FIG. 5  is a perspective elevation of the ATT mechanism  400  depicted in  FIG. 4  with the ATT mechanism inverted. Accordingly, the suction device  410  is at the nethermost location of the ATT mechanism  400  as depicted. The plurality of probe tips are provided as two probe tips per corresponding die pocket of a 10-die pocket die tray, one of which is designated by the reference numeral  424 . The spacer foot  412  is disposed between the top header bar  414  and the bottom foot bar  416 . The plurality of probes  418  (depicted in phantom lines) is disposed through the bottom foot bar  416  in preparation for determining whether an obstruction has been encountered such as an unremoved die. 
     FIG. 6  is a method flow decision diagram  600  according to various embodiments. 
   At  610 , the method includes moving the ATT mechanism toward a die tray. 
   At  612 , the method includes a query whether the probe encounters an obstruction. If an obstruction is encountered, a process jam and/or an operator alert occurs at  614 . Accordingly, an operator may be alerted in order to locate the obstruction, particularly if the obstruction is a microelectronic die. 
   At  620 , the method includes removing the obstruction from the die tray. In an embodiment, the method includes an operator being the agent who removes the obstruction. In an embodiment, the obstruction is a die. 
   At  630 , the method includes moving the die tray with respect to the location of the test handler. 
     FIG. 7  is a schematic depiction of an ATT system  700 , according to an embodiment. The system  700  according to an embodiment includes a device such as a reliable-fast-small (RFS®) test handler  710 , manufactured by Delta Design, of San Diego, Calif., that includes an input auto tray lift  712 , an auto tray buffer  714 , a plurality of sort auto tray lifts  716 , and a dump  718 . In an embodiment, a computing system  720  is a device such as a desktop computer that is electrically coupled  722  to the RFS test handler  710 . The computing system  720  can include input mechanisms such as a keyboard  724  and a mouse  726  and an output device such as a monitor  728 . 
   In an embodiment, the ATT mechanism is referred to as a tray handler. Accordingly, the tray handler is coupled with a die tray that includes a die pocket. A sensor on the tray handler is a device such as the probe and/or the probe tip as set forth in this disclosure. Accordingly, the probe tip may be a protrusion that is extendable into a die pocket of a tray if the die pocket is devoid of an obstruction, but the sensor may also be an optical sensor that similarly detects whether a die pocket of a die tray is devoid of an obstruction. 
   Where the sensor is a protrusion, such as a probe tip, the tray handler is configured to include the protrusions being aligned away from a KOZ of a die that is placeable as the obstruction in the die pocket. In an embodiment, the die pocket is part of a plurality of 10 die pockets and accordingly, the protrusion is part of a plurality of 20 probe tips as set forth in this disclosure. Similarly according to an embodiment, where the die pocket is part of a plurality of n die pockets, the protrusion is part of a plurality of 2n protrusions, and each die pocket of the plurality of n die pockets corresponds to two protrusions of the plurality of 2n protrusions. 
   The Abstract is provided to comply with 37 C.F.R. §1.72(b) requiring an Abstract that will allow the reader to quickly ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 
   In the foregoing Detailed Description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate preferred embodiment. 
   It will be readily understood to those skilled in the art that various other changes in the details, material, and arrangements of the parts and method stages which have been described and illustrated in order to explain the nature of this invention may be made without departing from the principles and scope of the invention as expressed in the subjoined claims.