Abstract:
A disk separator device for stacking semiconductor wafers includes a first portion having a disk support surface for accepting one side of a disk and a second portion including a guiding surface obliquely oriented to the disk support surface. The guiding surface has a first edge adjacent a curvilinear perimeter of the wafer support surface and a second edge spaced outwardly from the first edge. The separator device is nestingly received adjacent other separators to maintain a desired alignment of a stack of disks and separators.

Description:
[0001]    This invention generally relates to packing disks. More particularly, this invention relates to a separator device for use in packing disks, such as semiconductor wafers. 
       BACKGROUND 
       [0002]    A variety of containers are used for packaging items such as semiconductor wafers. Extreme care must be exercised when handling such items because of their delicate nature. In the case of semiconductor wafers, the silicon structure is very fragile. Various approaches have been taken to ensure the integrity of the semiconductor wafers within such packages. 
         [0003]    A typical package or container has a top and a bottom that are selectively secured together. A wafer restraining portion within which the wafers are held during handling and shipping, for example, extends between the top and the bottom. Individual wafers placed adjacent each other typically are separated by an appropriate sheet of material. The conventional approach is to use foam disk pads at the ends of a stack of wafers to provide cushion for the wafers in the container. Sometimes the foam disk pads are inserted between wafers within a stack. 
         [0004]    While foam inserts do provide cushion, there are drawbacks and shortcomings associated with their use. Difficulties arise when the wafers are not securely maintained within the package. The wafer restraining portion typically has an inside dimension that is greater than an outside dimension of the wafers. Accordingly, there is the possibility for lateral movement of the wafers relative to each other during handling or shipping. Such lateral movement damages the wafers and often renders the circuitry supported on the wafers useless. 
         [0005]    There is a need for an improved way of packaging items such as semiconductor wafers to protect them from damage during shipping and handling. This invention addresses that need by providing a unique separator device for semiconductor wafers placed within a container. 
       SUMMARY OF THE INVENTION 
       [0006]    An exemplary separator device for stacking disks such as semiconductor wafers includes a first portion having a disk support surface for accepting one side of a disk and a second portion including a guiding surface obliquely oriented to the disk support surface. The guiding surface includes a first edge adjacent a curvilinear perimeter of the disk support surface and a second edge spaced outwardly from the first edge. 
         [0007]    The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a top perspective view of an example separator device. 
           [0009]      FIG. 2  is a front perspective view of the example separator device. 
           [0010]      FIG. 3  is a bottom perspective view of the example separator device. 
           [0011]      FIG. 4  is a cross-sectional view of a disk located on the example separator device. 
           [0012]      FIG. 5  is a cross-sectional view of example separator devices in a stacked position. 
           [0013]      FIG. 6  is a cross-sectional view of another example separator device in a stacked position. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]      FIGS. 1-4  illustrate an example separator device  10  and a disk  30 . In one example, the disk  30  comprises a semiconductor wafer. The separator device  10  includes a first portion  12  that includes a disk supporting surface  14 . A protrusion  16  extends from a surface of the first portion  12  in a direction generally opposite the disk supporting surface  14 . In this example, the protrusion  16  has a flat outermost surface  18 . 
         [0015]    A second portion  20  is located radially outward from the first portion  12 . The second portion  20  includes a guiding surface  22  obliquely oriented to the disk supporting surface  14  and a nesting surface  24  substantially parallel to the guiding surface  22 . The second portion  20  in this example includes a retainer surface  26  that is substantially perpendicular to the disk supporting surface  14 . 
         [0016]    The disk supporting surface  14  is dimensioned to provide support beneath at least some of a periphery of the disk  30 . The example disk supporting surface  14  has an at least partially curvilinear perimeter corresponding to the geometry of the outer periphery of the disk  30 . In this example, the separator device  10  is annular. 
         [0017]    The guiding surface  22  assists in placing the disk  30  onto the disk supporting surface  14 . The obliquely oriented guiding surface  22  provides a centering feature to ensure proper placement of the disk  30  onto the disk supporting surface  14 . 
         [0018]    This example includes the retainer surface  26  that maintains the disk  30  in a seated position on the disk supporting surface  14 . The retainer surface  26  prevents the disk  30  from shifting into another position relative to the separator device  10 . The edge  32  of the disk  30  is received adjacent the retainer surface  26 . 
         [0019]    A reinforcing member  28  is located between the disk supporting surface  14  and the surface  18 . The reinforcing member  28  provides some rigidity to resist undesired deformation of the separator device  10 . 
         [0020]    The separator device  10  is made from a polypropylene material in one example. The polypropylene possesses properties to control electrostatic discharge from the material to prevent damage to highly sensitive circuitry on semiconductor wafers, for example. 
         [0021]      FIG. 5  illustrates a plurality of example separator devices  10  and a plurality of disks  30  in a stacked position. The disks  30  are kept from contacting each other because of the separator devices  10  between them. 
         [0022]    A first separator device  10  is placed within a container  38 . The nesting surface  24  of the second portion  20  guides the separator device  10  into the container  38 . The protrusion  16  on the separator device  10  contacts a bottom wall  40  of the container  38  when fully inserted into the container  38 . The radially outer portion of the nesting surface  24  and the outer wall  42  cooperate to prevent lateral movement of the separator device  10 . The protrusion  16  creates a spacing between the bottom wall  40  of the container  38  and the disk  30 . 
         [0023]    One disk  30  is placed within the container  38  on top of (according to the drawing) the first separator device  10 . The edge  32  of the disk  30  may contact and follow the guiding surface  22  to facilitate seating the disk  30  in a location adjacent the retainer surface  26  and on the disk supporting surface  14  of the separator device  10 . 
         [0024]    A second separator device  10  is placed in the container  38  as shown. A nesting surface  24  of the second separator device  10  may contact the guiding surface  22  of the first separator device  10 . The guiding surface  22  of one separator device  10  and the nesting surface  24  of the second separator device  10  facilitate stacking multiple separator devices  10  in the container  38 . The protrusion  16  on the second separator device  10  is located radially inward from the second portion  20  and contacts the first disk  30  already in the container  38  when the second separator device  10  is properly aligned. 
         [0025]    Another disk  30  is next placed within the container on top of the second separator device  10 . Similarly, a third separator device  10  is placed in the container  38  followed by additional disks and separators. 
         [0026]    In another example, the disks  30  and separator devices  10  are pre-stacked and then inserted into the container  38  together. 
         [0027]    A plurality of spacers  44  can be placed in the container  38  in a known manner to fill remaining space in the container  38 . A lid  46  is placed on the container  38  in a known manner to secure the disks  30  within the container  38 . 
         [0028]    As best appreciated in  FIGS. 1-3 , the second portion  20  includes a plurality of slits or cut-away sections  130  that increase the flexibility of the second portion  20 . The slits  130  minimize stress on the disk support surface in the event the second portion  20  (e.g., the outer edge on the guiding surface) contacts a container sidewall. 
         [0029]      FIG. 6  illustrates another example separator device  110  for stacking disks  30 . The example separator device  110  is substantially similar to the separator device  10  of  FIGS. 1 through 5  except where noted or shown in  FIG. 6 . The separator device  110  includes a first portion  112  having a disk supporting surface  114 . A protrusion  116  extends from a surface of the first portion  112  in a direction generally opposite the disk supporting surface  114 . 
         [0030]    A second portion  120  is located radially outward from the first portion  112 . The second portion  120  includes a guiding surface  122  obliquely oriented to the disk supporting surface  114  and a nesting surface  124  substantially parallel to the guiding surface  122 . 
         [0031]    A reinforcing member  128  is located radially inward from the first portion  112 . The reinforcing member  128  is located between the disk supporting surface  114  and a surface  118 . The reinforcing member  128  provides some rigidity to resist undesired deformation of the separator device  110 . 
         [0032]    One difference between this example and the example of  FIG. 5  is that there is no retainer surface at the location where the guiding surface  122  meets the disk support surface  114 . 
         [0033]    A plurality of example separator devices  110  and a plurality of disks  30  may be stacked as shown in  FIG. 6 . 
         [0034]    With either example separator device, the contact between the separator devices  10 ,  110  and the disks  30  is controlled. There is minimal, if any, chance of misalignment that would introduce the possibility of damage to the disks  30 . The nesting separator devices and the seating of the disks  30  in each separator device ensures a consistent and reliable alignment within a container. Inserting and removing disks is also better with the disclosed examples. 
         [0035]    While preferred embodiments of the invention has been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the scope of the invention.