Abstract:
A stacking tray for electrical components, such as integrated circuit chips, particularly those of the ball grid array (BGA) type is disclosed. The tray is stackable and includes an upper side and a lower side. An array of storage pockets is formed between the upper side of a lower tray and the lower side of an upper tray. The storage pockets are separated by complementary support elements and further include a segmented pedestal arising from the center of the storage pocket, on the upper side of the trays. The segmented pedestal supports the integrated circuit chip, without interfering with the spherical balls. Moreover, the tray allows for variation of the dimensions of the integrated circuit chip while adequately stabilizing the chip.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention pertains to a tray for the storage and transportation of integrated circuit chips, particularly ball grid array (BGA) chips. 
         [0003]    2. Description of the Prior Art 
         [0004]    The need for mechanical and electrostatic protection of integrated circuit chips during storage and transportation is firmly established in the prior art. The use of stacking trays for the storage and transportation of integrated circuit chips, as well as for providing the trays in an unstacked configuration for subsequent pick-and-place operations, is well developed and is particularly well adapted for its intended purposes. However, the wide variety of dimensions and configurations (which may be as subtle as edge clearance, ball pitch or device thickness) of integrated circuit chips makes it difficult to assure that a properly sized tray will be available for the many different integrated circuit chips which may need to be stored or transported from a given location, particularly if the trays are configured to hold the chips by their edges within pockets of the trays. This can be a particular concern for ball grid array (BGA) chips which include spherical protrusions which must be accommodated without compromising the mechanical or electrostatic protection. 
         [0005]    Some examples of the prior art stackable trays can be found in U.S. Pat. No. 5,400,904 entitled “Tray for Ball Terminal Integrated Circuits”, issued to Maston et al. on Mar. 28, 1995; U.S. Pat. No. 5,103,976 entitled “Tray for Integrated Circuits with Supporting Ribs”, issued to Murphy on Apr. 14, 1992; U.S. Pat. No. 5,080,228 entitled “Integral Carrier and System for Electrical Components”, issued to Maston et al. on Jan. 14, 1992; U.S. Pat. No. 5,000,697 entitled “Carrier System for PGA Electrical Components”, issued to Murphy on Mar. 19, 1991; U.S. Pat. No. 4,765,471 entitled “Electrical Component Carrier”, issued to Murphy on Aug. 23, 1988. 
         [0006]    Additional examples can be found in commonly owned U.S. patent application Ser. No. 10/414,617, filed on Apr. 16, 2003 entitled “Stackable Tray for Integrated Circuits with Corner Support Elements and Lateral Support Elements Forming Matrix Tray Capture System” and commonly owned U.S. patent application Ser. No. 11/057,343, filed on Feb. 14, 2005, entitled “Stackable Tray for Integrated Circuit Chips”. 
       OBJECTS AND SUMMARY OF THE INVENTION 
       [0007]    It is therefore an object of the present invention to provide an apparatus and method for the storage of integrated circuit chips, particularly ball grid array (BGA) chips. 
         [0008]    It is therefore a further object of the present invention to provide an apparatus and method for the storage and shipment of integrated circuit chips of different dimensions within a single device. 
         [0009]    These and other objects are attained by providing stacking trays with storage pockets formed on the upper and lower surfaces. Successive trays may be stacked so that the storage pockets on the upper surface of a storage tray align with the storage pockets on the lower surface of an upwardly adjacent tray to form storage pockets to retain the integrated circuit chips. The storage pocket on an upper surface of the trays contains a central segmented pedestal. The pedestal stabilizes and supports the integrated circuit chip from underneath so that the integrated circuit chip, particularly a BGA chip, is supported in an area that is not populated with the device spherical interconnecting balls. The segmented pedestal lifts the integrated circuit chip from the floor of the tray to not allow contact of the integrated circuit chips spheres to other portions of the tray when the trays are tilted. The pedestal is typically segmented to allow for variations in the integrated circuit chip, particularly domes which may form on the lower surface of a BGA integrated circuit chip. Additionally, the segments typically further include ears or protrusions to further stabilize the integrated circuit chip supported by the pedestal. These ears are configured and arranged so to not interfere with the sphere array of the supported device. 
         [0010]    The tray conforms to JEDEC standards which sets the tray outline, storage pocket locations, outer rail height and stacking configuration which permits an integrated circuit chip seated in a full storage pocket defined by a lower tray storage pocket and an upper tray storage pocket to be restrained and stabilized. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0011]    Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a top perspective view of the tray of the present invention. 
           [0013]      FIG. 2  is a bottom perspective view of the tray of the present invention. 
           [0014]      FIG. 3  shows an area of detail of  FIG. 1 . 
           [0015]      FIG. 4  shows an area of detail of  FIG. 2 . 
           [0016]      FIG. 5  is a top plan view of the tray of the present invention. 
           [0017]      FIG. 6  is a cross-sectional view along plane  6 - 6  of  FIG. 5 . 
           [0018]      FIG. 7  is a bottom plan view of the tray of the present invention. 
           [0019]      FIG. 8  is a cross-sectional view, formed along the diagonal of a storage pocket formed by two successive trays of the present invention, showing a ball grid array (BGA) integrated circuit chip secured therein. 
           [0020]      FIG. 9  is a perspective view of the configuration of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0021]    Referring now to the drawings in detail wherein like numerals refer to like elements throughout the several views, one sees that  FIG. 1  is a top perspective view of the tray  10  of the present invention,  FIG. 2  is a bottom perspective view of the tray  10  of the present invention,  FIG. 5  is a top plan view of the tray  10  of the present invention and  FIG. 7  is a bottom plan view of the tray  10  of the present invention. Tray  10  conforms to the standards of JEDEC and hence is bounded by long sides  12 ,  16  and short sides  14 ,  18  with interior structure provided by planar floor  20 . Sides  12 ,  14 ,  16 ,  18  are bounded by downwardly extending peripheral skirt  22  (see  FIG. 6 ) which further includes upper indentation  24  for receiving the peripheral skirt  22  of an upwardly adjacent tray thereby allowing the trays  10  to be stacked. Flanges  26 ,  28  are provided on short sides  14 ,  18  offset from one another in accordance with JEDEC standards to provide indication of the front and back of the tray. Additionally, as shown on  FIG. 5 , the upper interior surface of sides  12 ,  14 ,  16 ,  18  include respective tab pairs  13 ,  15 ,  17 ,  19  for receiving the respective corresponding tabs  21 ,  23 ,  25 ,  27  on the lower interior surface of sides  12 ,  14 ,  16 ,  18  of a successive identical upper tray  10 , thereby aligning successive trays  10  in a stacked configuration. As noted, the entire peripheral structure, including peripheral skirt  22 , upper indentation  24  and flanges  26 ,  28 , is made in accordance with JEDEC standards to provide for standardized automated handling of tray  10 . 
         [0022]    Corner  30  is formed at the intersection of sides  12 ,  14 . Corner  32  is formed at the intersection of sides  14 ,  16 . Corner  34  is formed at the intersection of sides  16 ,  18 . Corner  36  is formed at the intersection of sides  12 ,  18 . L-shaped support elements  40  are formed on the upper surface or side ( FIGS. 1 ,  3  and  5 ) inwardly adjacent from corners  30 ,  32 ,  34 ,  36 . T-shaped support elements  44  are formed inwardly adjacent from sides  12 ,  14 ,  16 ,  18  on the upper surface of tray  10 , and X-shaped support elements  46  are formed on the upper surface in the interior of tray  10  thereby defining storage pockets  101 - 121  (see  FIGS. 5 and 7 ) which are configured in rows and columns within the rectangular shape of tray  10 , which could likewise be provided in a square or other shape. Storage pockets  109 ,  111 ,  113  include a solid planar floor  20  thereby forming vacuum storage pockets to permit vacuum operated equipment to couple to the tray  10  whereas the remaining storage pockets have a substantial portion of planar floor  20  removed as described below. Additionally, support elements  40 ,  44 ,  46  typically have beveled upper (in the configuration or orientation of  FIGS. 1 and 3 ) surfaces. 
         [0023]    As shown in  FIGS. 2 ,  4  and  7 , the lower surface or side of tray  10  includes L-shaped support elements  52  inwardly adjacent from corners  30 ,  32 ,  34 ,  36 . As best seen in  FIG. 4 , L-shaped support elements  52  include legs  54 ,  56  oriented perpendicular to each other, meeting at apex  58 , with an outer portion of legs  54 ,  56  removed adjacent to apex  58  in order to allow the corresponding L-shaped support element  40  from the upper surface of a downwardly successive tray  10  to seat on L-shaped support element  52 . Additionally, the inner portion of legs  54 ,  56  have a reduced height, and ledge  59  of this reduced height is formed along the interior of L-shaped support element  52 . T-shaped support elements  60  are formed inwardly adjacent from sides  12 ,  14 ,  16 ,  18  on the lower surface of tray  10 . T-shaped support elements  60  are formed from collinear head segments  62 ,  64  which are parallel to the immediately adjacent side of the tray and further formed from segment  66  which is perpendicular to the head segments  62 ,  64 . A portion of the interior of segment  66  immediately adjacent to the intersection  68  of segments  62 ,  64 ,  66  is removed thereby forming slot  67 . Similarly, an outer portion of the collinear head segments  62 ,  64  immediately adjacent to the intersection  68  is removed in order, along with slot  67 , to form a seat to receive the corresponding T-shaped support element  44  from the upper surface of a downwardly successive tray  10 . Additionally, the inner portion of segments  62 ,  64 ,  66  have a reduced height, and ledge  69  of this reduced height is formed on both sides of segment  66  and along the interior of segments  62 ,  64 . 
         [0024]    X-shaped support elements  70  are formed from four segments  71 ,  72 ,  73 ,  74  at successive right angles to each other, joining at center  75 . The interior of each four segments  71 ,  72 ,  73 ,  74  is removed thereby forming slots in order to form a seat to receive the corresponding X-shaped element  46  from an upper surface of a downwardly successive tray  10 . Additionally, the inner portion of segments  71 ,  72 ,  73 ,  74  have a reduced height, and ledge  77  of this reduced height is formed along both sides of segments  71 ,  72 ,  73 ,  74 . Typically, ledges  59 ,  69  and  77  are of equal height. 
         [0025]    Support elements  52 ,  60 ,  70  typically include beveled upper (in the configuration or orientation of  FIGS. 2 and 4 ) surfaces and are formed directly below respective support elements  40 ,  44 ,  46 . 
         [0026]    As shown in  FIGS. 1 ,  3 , and  5 , the upper surface of tray  10  (which forms the lower surface of the storage pockets  101 - 121 ) includes, in each storage pocket other than vacuum storage pockets  109 ,  111 ,  113 , eight octant-oriented apertures  201 - 208 . Rotationally segmented pedestal  210 , comprised of segments  212 ,  214 ,  216 ,  218 , each forming approximately a quarter circle, arise from the center of each storage pocket on the upper surface of the tray  10 . Segment  212  spans apertures  201 ,  202 . Segment  214  spans apertures  203 ,  204 . Segment  216  spans apertures  205 ,  206 . Segment  218  spans apertures  207 ,  208 . The midpoint of segments  212 ,  214 ,  216 ,  218  includes respective outwardly or diagonally extending protrusions or ears  220 ,  222 ,  224 ,  226 . Protrusions or ears  220 ,  222 ,  224 ,  226  extend toward respective corners of the storage pocket, thereby extending toward the respective corners of the integrated circuit chip  1000  contained therein, thereby providing additional support to the integrated circuit chip  1000  (see  FIGS. 8 and 9 ). 
         [0027]    As shown in  FIGS. 8 and 9 , the integrated circuit chip  1000  is captured between successive trays  10 . Pedestal  210  supports the integrated circuit chip  1000  while being sufficiently spaced from the various support elements to allow the spherical balls  1002  to point downwardly without being contacted by pedestal  210  or any other portion. The edges of integrated circuit chip  1000  are likewise captured between the corresponding support elements of the successive trays  10 . However, as shown in  FIG. 8 , this configuration allows for variations in the dimensions of integrated circuit chip  1000  wherein the edge on the illustrated left side is firmly engaged or stabilized in both the direction perpendicular to the tray  10  and directions parallel to the tray  10 , while the edge on the illustrated right side is less firmly engaged, yet the integrated circuit chip  1000  remains well stabilized without excessive tilt. 
         [0028]    Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.