Abstract:
A method for dispensing, receiving, storing, testing or binning packaged integrated circuit devices using at least one vertically oriented, removable, tubular magazine disposed above a controllably driven, rod-like indexing element extending from a drive below the magazine. A magazine, with an associated indexing element and drive, is configurable as an individual magazine module. The indexing element, under power of the drive, raises or lowers a vertical stack of devices to a desired level adjacent the top of the magazine to dispense or receive an individual device from a feed mechanism, such as a pick-and-place mechanism. A number of magazine modules may be assembled in a multi-module array, which is particularly suitable for binning tested devices, with a sort category being directed to each magazine.

Description:
RELATED APPLICATIONS 
     This application is a divisional of application Ser. No. 09/008,228, filed Jan. 16, 1998, now U.S. Pat. No. 6,135,291, issued Oct. 24, 2000. This application contains subject matter related to U.S. patent application Ser. No. 09/008,227, filed Jan. 16, 1998, now U.S. Pat. No. 6,112,940, issued Sep.5, 2000, and entitled Vertical Magazine Apparatus for Integrated Circuit Device Dispensing, Receiving or Storing, by the same inventor. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to methods for optionally dispensing, receiving or storing semiconductor devices including integrated circuits and, more specifically, to methods employing vertical stacking of such devices in magazines. 
     As the semiconductor industry advances in the fabrication and processing of packaged semiconductor devices (sometimes referred to herein for convenience as “devices”), such as thin small outline packages, or TSOPs, testing and sorting of such devices pose challenges in terms of device throughput, test equipment space utilization, and device distribution responsive to test result-responsive sorting. 
     Currently, processing of thin package devices such as TSOPs is primarily carried out based upon specialized JEDEC (Joint Electronic Device Engineering Council) specification trays, which are approximately five inches wide by twelve inches long. The JEDEC tray design dictates that the semiconductor devices are carried in a single layer, arranged in mutually perpendicular rows and columns. Tray density, or the number of devices carried by each tray, obviously decreases as device size increases. For reference purposes, if a given device is 0.400 inch wide by 0.750 inch long, a JEDEC tray part capacity, with a nine row by thirteen column configuration, is about 117 parts per tray. 
     Testing of the devices is conventionally carried out in batches of thirty-two parts (devices) run through a test cycle simultaneously. The devices are then sorted into a number of categories based upon test results and then “binned” into the aforementioned JEDEC trays by a conventional “pick-and-place” robotic arm system. At the present time, as many as sixteen sort categories are employed, and it is anticipated that the number of sort categories will increase as the sophistication and miniaturization of semiconductor devices continue in the future. If each JEDEC tray employed for receiving post-test devices is intended to receive a single bin or sort category, a substantial amount of manufacturing floor space is required to accommodate an arrangement where sixteen JEDEC trays are placed in a horizontal array. Further, the size and complexity of the pick-and-place device required to place tested devices in the trays of such an array become unreasonable. Alternatively, if (for example) sixteen JEDEC trays are stacked in a holding tower in a vertical format, wherein the trays themselves are again horizontally oriented but mutually vertically superimposed, a tray retrieval and presentation mechanism is required. Further, the time to retrieve each tray from the tower, present it for pick-and-placement of a tested device, and replace the tray in the tower severely limits device throughput. As the number of sort categories increases, each of the foregoing approaches to device binning becomes ever-more unwieldy to execute. 
     Thus, the prior art approach to semiconductor device sorting and binning has demonstrated severe deficiencies in terms of throughput, space utilization, and complexity of required device handling equipment. 
     SUMMARY OF THE INVENTION 
     The present invention affords a simple, elegant and economical solution to the previously identified problems with device sorting and binning. By employing a vertical binning approach instead of the prior art horizontal binning approach, embodiments of the present invention offer the ability to simulate the horizontal spatial configuration or “footprint” of a JEDEC tray for convenience of use with conventional, unmodified robotic pick-and-place equipment. Additional embodiments of the invention enable the binning of tested and sorted devices into an extremely high number of categories in a rapid, accurate manner and subsequent storage, transport and dispensing of the binned devices for subsequent operations. 
     One embodiment of the invention includes at least one elongated magazine configured for containing a plurality of semiconductor devices, including by way of example thin package devices, in a stacked configuration. The magazine is mounted substantially vertically and removably associated with an indexing element of an elevation assembly, the indexing element being movable to regulate the internal longitudinal volume of the interior of the magazine, in order to receive or present a device at a desired level proximate the top of the magazine from a stack of devices within the magazine. The indexing element may be driven by a stepper motor or other incrementally or continuously controllable drive employed in the elevation assembly to ensure presentation or receipt of the top device in the magazine at a correct, controllable vertical height for easy access by a pick-and-place system. The magazine and elevation assembly together may be said to comprise a magazine unit. 
     It is currently contemplated that a best mode of implementation of the invention may involve a plurality of magazine units in modular form placed in an array, each including a removable, vertically extending magazine placed in close mutual horizontal proximity and, if desired, in a pattern to simulate at least some of the rows and columns exhibited by the aforementioned JEDEC trays. Thus, each magazine is associated with an indexing element responsive to a separately controllable drive of a discrete elevation assembly for raising or lowering a stack of devices within that magazine to either present an uppermost device in a magazine stack for retrieval, or to lower an uppermost device in a stack to provide a location for placement of another device in that magazine. 
     Embodiments of the invention also include a method of binning devices and a method of dispensing stored devices for further handling. 
    
    
     DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a perspective view of a single magazine module embodiment of the invention; 
     FIG. 1A is a top elevation of the magazine depicted in FIG. 1; 
     FIG. 1B is a side sectional elevation of a mid-portion of the magazine depicted in FIG. 1; 
     FIG. 2 is a perspective view of a multiple magazine module embodiment of the invention; 
     FIG. 3 is a top view of a single magazine embodiment configured for containment of multiple vertical stacks of devices; 
     FIG. 4 is a schematic depicting dispensing, testing, and binning of devices according to the present invention; 
     FIG. 5 is a schematic of a square, four magazine module by four magazine module array of one embodiment of the invention; 
     FIG. 6 is a linear, eight magazine module array of one embodiment of the invention; 
     FIG. 7 is a schematic top elevation of two module arrays alternately movable into a target field of a pick-and-place mechanism; 
     FIG. 8 is a schematic top elevation of an elongated two module deep linear array translatable across the target field of a pick-and-place mechanism; and 
     FIG. 9 is a schematic top elevation of a circular, carousel-type array rotatable into the target field of a pick-and-place mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, magazine unit  10  comprises an elongated, generally tubular magazine  12  defining an interior cavity  14 , the cross-section of which may be varied in size and shape responsive to that of the devices  100  (such as the aforementioned TSOPs) to be contained therein. Magazine  12  may be formed of any suitable metallic or non-metallic material, although it is contemplated that it be molded from an anti-electrostatic discharge (ESD) polymer, or coated with such a material. As shown, magazine cavity  14  is sized to accommodate a plurality of devices  100  stacked in vertically superimposed relationship. Also as shown, one or more walls of magazine  12  may include an elongated view port  16 , so that the filled versus empty status of the magazine may be visually verified as desired. It is also desirable that magazine  12  include a floor  18  movable within interior cavity  14 . As shown in FIG. 1A, floor  18  is preferably larger than aperture  14   a  at the bottom of interior cavity  14 , so that devices  100  in magazine  12  will be retained from below by floor  18  when magazine  12  is being handled. As shown in. FIG. 1B, floor  18  may include skirts or other peripheral extensions  18   a  to prevent tilting, cocking and jamming of floor  18  as it moves up and down within magazine cavity  14 . 
     Magazine  12  is placed above an elevation assembly  20  at a fixed vertical level L, and may be stabbed into a fixture, depicted in FIG. 1 as receptacle  22  (shown in broken lines), to provide proper horizontal, vertical and angular (about a vertical axis) orientation for magazine  12 . It is preferred, although not required, that magazine  12  be secured against vertical movement by a detent assembly comprised of one or more resiliently biased detent elements  24  cooperating with a like number of recesses  26  in a sidewall of magazine  12 . The detent assembly may comprise a leaf-spring biased detent element as shown, or biasing may be provided by a coil spring, a resilient elastomer, or otherwise as known in the art, or may comprise a resilient wall portion molded into receptacle  22 . Alternatively, magazine  12  may be frictionally retained within receptacle  22 , or may be positively locked within receptacle  22  by a latch or pin-type locking arrangement, such mechanisms being conventional. 
     An elongated, rod-like indexing element  30  is extendable upwardly into interior cavity  14  of magazine  12  under the power and control of drive  32 , which may comprise a stepper motor, a screw drive, or other suitable incrementally or continuously controllable drive mechanism as known in the art. As shown, indexing element  30  extends vertically through drive  32  and upwardly into magazine  12 , where it contacts the bottom of floor  18 . As shown in FIGS. 1A and 1B, element  30  may be received within a cup  34  formed in the bottom of floor  18 . Cup  34 , like skirts  18   a , may alleviate any tendency of floor  18  to tilt, cock or jam. If desired, the upper end of indexing element  30  may be of rectangular or other suitable cross-section, and the interior blind bore of cup  34  configured to mate therewith. Drive  32  may be controlled responsive to removal or addition of a device to its associated magazine  12  by a pick-and-place mechanism to, respectively, extend or retract indexing element  30  by an increment equivalent to the depth (thickness) of a given device  100 . Such movement may be software controlled for ease of accommodating different devices  100 . 
     Optionally and desirably, each magazine  12  may carry identifying indicia or an identification device thereon to facilitate proper identification and use of a given magazine and its contents. For example, as shown in FIG. 1, magazine  12  may bear an identification device  40  such as a bar code or magnetic strip (such as is employed with credit cards) on an exterior sidewall thereof. Alternatively, and again as shown in FIG. 1, magazine  12  may bear a more sophisticated electronic identification device  42  utilizing a memory device such as an EEPROM or flash memory. An RFID (Radio Frequency Identification) device may also be employed for enhanced remote inventory and theft control through electronic tracking or monitoring. Such bar code  40  or identification devices  42  may be employed to retain and provide “bin” information as to the test characteristics exhibited by the binned devices carried by the magazine, part count, manufacturing origin, test date, test equipment, test protocol, and other useful information, such as the location of a specific part in a stack of parts deposited in a given magazine  12 . 
     As depicted in FIG. 2, a plurality of magazine units  10 , optionally in identical modular form (hereinafter “magazine modules”), may be arranged in a close horizontally adjacent array  110  to dispense or receive devices  100  in association with a pick-and-place mechanism. This arrangement is particularly beneficial for receiving tested and sorted devices  100 , with each magazine  12  of the array  110  comprising a “bin” to receive devices exhibiting particular characteristics under test and sorted accordingly. As shown in broken lines  60 , the magazine module array  110  may be arranged to simulate the device containment pattern size and shape of the aforementioned JEDEC trays, while eliminating the previously described conventional practice of presenting different trays for receiving differently binned devices. Moreover, using the invention, a pick-and-place mechanism may thus be programmed to dispense tested, sorted chips to only one specific X-Y plane (transverse to the axes of magazines  12 ) location for each sort category, or bin, of tested devices. 
     As desired, the magazine units or modules  10  may be arranged to comprise a square array (for example, four modules  10  by four modules as shown in FIG.  5 ), another rectangular array (for example, four modules  10  by two modules  10  as shown in FIG.  2 ), a linear array (for example, a line of eight modules as shown in FIG.  6 ), or in any other desired arrangement. Further, and again as desired, two or more module arrays  110  may be employed if a large number of bins are required and the pick-and-place device  120  has a limited horizontal travel, the multiple arrays  110  being alternatively placeable within reach of a target field  124  of the pick-and-pace arm  122 , as shown in FIG.  7 . Also, a longitudinally extended module array  110  may be mounted so as to be linearly translatable through a target field  124  of a pick-and-place arm  122 , as shown in FIG.  8 . Finally, and as illustrated in FIG. 9, a circular carousel-type array  110  may be employed to rapidly, rotationally present each magazine module  10  at the same, specific, fixed target field  124  for pick-and-place. 
     As shown in both FIGS. 1 and 2, the magazine modules  10  may be easily bolted or otherwise secured by fasteners to a module or array support plate in any desired pattern and spacing using apertures  72  in flange plates  70  at the tops of drives  32 . Alternatively, the magazine modules  10  may be frictionally seated in recesses in a support, spring-loaded or positively locked clamps may be employed to retain magazine modules  10 , resiliently biased detent devices employed, or any other suitable retention structure known in the art. Further, drives  32  may be linked to a test apparatus and sorting device by quick-release electrical connections (such as male-female connectors, resiliently biased surface contacts, or other suitable connections known in the art). 
     When a given magazine  12  is completely filled, such status being conveyed to the operator by, for example, a sensor  50  (see FIG. 1) sensing the position of indexing element  30  or a proximity sensor  52  (see FIG. 1) located on the interior of receptacle  22  sensing the proximity of floor  18  to the bottom of that magazine  12 , the full magazine  12  is removed and replaced by an empty one. Triggering of such sensors  50 ,  52  may result in an alarm or other indicator to alert the operator, and a signal to a control system to stop the binning process until the full magazine is replaced. Furthermore, such sensors may sense, and/or effect the indication of, the number of devices  100  present in the magazine  12 . Position sensor  50  may sense actual travel of indexing element  30 , or may merely react to proximity of an indicator located on the shaft of indexing element  30 . Proximity sensor  52  may comprise a contact switch, a photocell, a reflection type optical encoder, an ultrasound sensor, or other suitable sensor known in the art. In lieu of being associated with receptacle  22 , proximity sensor  52  may be built into the lower end of each magazine  12 , and electrical contact for providing power and passing a signal from the sensor made with a host device such as a programmed computer associated (for example) with a testing device or a sorting device when magazine  12  is plugged into receptacle  22 . Male\female mating contacts, resiliently biased surface contacts, or other conventional arrangement may be employed to make the connection. 
     Position sensor  50  might also be employed to indicate when a dispensing magazine  12  has been emptied (i.e., indexing element  30  is at full extension), and a proximity sensor  52   a  might be employed at the top of each dispensing magazine  12  to signal the proximity of floor  18  to the mouth  14   b  of interior magazine cavity  14 , proximity sensor  52   a  having a quick-disconnect electrical connection  54  associated therewith for connecting proximity sensor  52   a  to an alarm or other indicator, to the control for the mechanism being fed by the magazine, and to the control for elevator drive  32 . Alternatively, the connection for proximity sensor  52   a  may be located at the bottom of magazine  12  so that entry of the bottom of magazine  12  into a receptacle  22  also effects an electrical connection for the sensor. Further, the sensor may extend longitudinally along the vertical length of the magazine as shown at  52   b , to sense the proximity of the floor  18  in a continuous manner, and thus the magnitude of the interior cavity  14  of the magazine  12  above floor  18  on a continuous basis. In a very simple form, the “sensor” may comprise a graduated indicator scale  52   c  inscribed on the exterior of magazine  12  next to view port  16  in gradations equal to the thickness of the devices contained therein and numbered to visually indicate the number of devices in the magazine, the remaining magazine capacity, or both. Alternatively, the scale  52   c  may be printed on an adhesive-backed strip or film to be removably adhered to a magazine  12  so that different scales may be used for devices of different thicknesses. 
     As shown in FIG. 3, the magazine of the present invention may be configured in an embodiment  210  to present or receive a plurality, for example four ( 4 ), of devices  100  by employing four interior cavities  14  arranged about a central passage  212  for receiving an indexing element  30 , the floors  18  within the four interior cavities  14  being linked to a central support  214  which is engaged by indexing element  30 . 
     FIG. 4 schematically depicts the dispensing of devices  100  from an array  110   a  of magazine units  10  according to the present invention, retrieval with arm  122   a  of a pick-and-place mechanism  120   a  and placement into a test board  128  preparatory to passage through test apparatus  130  for electrical testing (optionally at elevated temperature) and sorting of devices  100  as known in the art, retrieval of tested devices  100  with arm  122   b  of a second pick-and-place mechanism  120   b  and binning of same into additional magazine units  10  in an array  110   b  in accordance with their exhibited test characteristics. Other types of device handling mechanisms may also be employed, and it is specifically contemplated that a translatable chute-type gravity feed mechanism is suitable for dispensing tested devices  100  into various magazines  12  in accordance with their test characteristics. Many types of such electrical tests being known and conventionally practiced in the art, and the type of such tests being unrelated to the present invention and its practice, no further description thereof will be made herein. 
     The present invention has been disclosed as having specific utility with TSOP devices. However, it is contemplated as having utility with any type of semiconductor device, particularly packaged devices such as (for example) small outline j-lead (SOJ) devices, thin quad flat pack (TQFP) devices, dual-in-line package (DIP) devices, ball grid array (BGA) devices, and chip scale package (CSP) devices. 
     While the present invention has been described in terms of certain illustrated embodiments, those of ordinary skill in the art will readily recognize that it is not so limited. Many additions, deletions and modifications may be made to the embodiments disclosed, as well as combinations of features from different disclosed embodiments, without departing from the scope of the invention as hereinafter claimed.