Single and dual stage wafer cushion and wafer separator

Abstract

Improvements in a single and dual stage wafer cushion is disclosed where the wafer cushion can use an edge hinge as a single first stage cushion and a second mid span hinge for the dual stage wafer cushion. This dual stage design gives two distinctly different cushioning forces as opposed to using a single stage design where the force is linear with the amount of compression that is being applied to the outer surfaces of the wafer cushion. The outside edge of the ring provides the greatest expansion such that only the outer edge of the ring makes contact with the outer edge of a wafer. The wafer cushion is a material that flexes and absorbs shocks before the shock is transferred to the wafer stack. The material minimizes debris or contaminants from embedding into the wafer cushion and also prevents sheading of material from the wafer cushion.

1 . A wafer separator comprising:
 an outer peripheral portion;   said outer peripheral portion having a top surface and a bottom surface;   cushion having essentially a ring shape;   a middle surface having a diameter that is less than said outer peripheral portion and being disposed between said top surface and said bottom surface for placement of a wafer;   said middle surface extends to an inside diameter that provides and open central area, and   at least one vent disposed on said bottom surface that extends from said inside diameter to said outer peripheral portion.   
     
     
         2 . The wafer separator according to  claim 1  wherein said at least one vent is sized to provide an air cushion chamber below said wafer. 
     
     
         3 . The wafer separator according to  claim 1  wherein said open central area provides clearance of clearance of components, bond pads, solder bumps, solder balls, post passivation interconnects, and conductor lines on said wafer. 
     
     
         4 . The wafer separator according to  claim 1  wherein said open central area provides clearance of clearance of components, bond pads, solder bumps, solder balls, post passivation interconnects, and conductor lines on an adjacent wafer. 
     
     
         5 . The wafer separator according to  claim 1  wherein said wafer is 200 or 300 mm. 
     
     
         6 . The wafer separator according to  claim 1  wherein wafer separators are stacked on said top surface and said bottom surface without placing any loading on said wafer. 
     
     
         7 . The wafer separator according to  claim 1  wherein said at least one vent is “V”, “U”, square, rectangular or a combination thereof in profile. 
     
     
         8 . The wafer separator according to  claim 1  wherein said outer peripheral portion is sized to fit within a wafer carrier. 
     
     
         9 . The wafer separator according to  claim 1  wherein said at least one vent is a plurality of vents that are equally spaced around said bottom surface. 
     
     
         10 . The wafer separator according to  claim 9  wherein said plurality of vents is variable based upon a dimension of said outer peripheral portion. 
     
     
         11 . The wafer separator according to  claim 9  wherein said plurality of vents is variable based upon a volume of air under said wafer. 
     
     
         12 . The wafer separator according to  claim 1  wherein said at least one vent extends radially from said inside diameter to said outer peripheral portion. 
     
     
         13 . The wafer separator according to  claim 1  wherein said middle surface is angled. 
     
     
         14 . The wafer separator according to  claim 1  wherein said bottom surface is angled. 
     
     
         15 . The wafer separator according to  claim 1  wherein said wafer separator is made from a compliant material having a hardness of shore D of between 10 and 70. 
     
     
         16 . The wafer separator according to  claim 1  wherein said vent terminates with a radius or round where said vent terminates at said outer peripheral portion. 
     
     
         17 . The wafer separator according to  claim 1  that further includes a mid-diameter wall between said outer peripheral portions and said inside diameter. 
     
     
         18 . The wafer separator according to  claim 17  wherein said mid-diameter wall is sized to fit the outside diameter of a wafer. 
     
     
         19 . The wafer separator according to  claim 1  wherein said vent is configured to vent between said bottom surface of a first wafer separator and a top surface of a second wafer separator without venting on a surface of a wafer. 
     
     
         20 . The wafer separator according to  claim 1  wherein said wafer separator does not have a rotational orientation.