Thin Material Handling Carrier

Abstract

A wafer carrier that exhibits a thin, low-profile includes a bottom support plate upon which a thinned semiconductor wafer may be positioned, with a holding ring disposed to surround the periphery of the wafer and engage with the bottom support plate to hold the wafer in a fixed position between the two components. The bottom support plate is formed to include a plurality of apertures for pulling a vacuum through the carrier, as well as features that engage with the holding ring and alignment fiducials for properly registering the orientation of the wafer's surface with respect to the wafer carrier and other testing equipment using the wafer carrier.

What is claimed: 
     
         1 . A wafer carrier comprising:
 a bottom support plate upon which a thinned wafer may be positioned, the bottom support plate having a flat top surface for maintaining contact with a facing surface of the thinned wafer, the bottom support plate including a plurality of apertures formed through the thickness thereof configured to access a vacuum force and maintain the thinned wafer in place during subsequent operations; and   a holding ring disposed to surround the periphery of the thinned wafer and engage with the bottom support plate to hold the thinned wafer in a fixed position between the bottom support plate and the holding ring.   
     
     
         2 . The wafer carrier as defined in  claim 1 , where the flat top surface of the bottom support plate exhibits a variation in thickness of ±5 μm or less. 
     
     
         3 . The wafer carrier as defined in  claim 1 , where the plurality of apertures is disposed in a pattern of concentric circles across the flat top surface of the bottom support plate. 
     
     
         4 . The wafer carrier as defined in  claim 3 , where individual apertures forming the plurality of apertures are positioned in a defined spacing between adjacent apertures on a defined circle of the plurality of concentric circles, with the spacing between adjacent circles further defined to coordinate with an arrangement of vacuum apertures included on equipment used for subsequent operations. 
     
     
         5 . The wafer carrier as defined in  claim 1 , wherein the bottom support plate further comprises at least one alignment fiducial formed at a defined location at a peripheral edge location, the at least one alignment fiducial providing registration between the thinned wafer and the bottom support plate. 
     
     
         6 . The wafer carrier as defined in  claim 5 , wherein the bottom support plate further comprises at least one alignment slot extending outward from the at least one alignment fiducial, the at least one alignment slot for providing positioning of the wafer carrier with respect to equipment used for subsequent operations. 
     
     
         7 . The wafer carrier as defined in  claim 1 , wherein the bottom support plate further comprises at least one registration element formed on a bottom surface thereof, the at least one registration element providing alignment between the wafer carrier and the equipment used for subsequent operations such that vacuum apertures of the equipment align with the plurality of apertures of the bottom support plate, providing an effective vacuum force to secure the thinned wafer in place during subsequent operations. 
     
     
         8 . The wafer carrier as defined in  claim 1 , wherein the bottom support plate is formed of a conductive material for facilitating selected testing of the thinned wafer. 
     
     
         9 . The wafer carrier as defined in  claim 1 , wherein the bottom support plate is formed of an insulating material. 
     
     
         10 . The wafer carrier as defined in  claim 1 , wherein the wafer carrier further comprises a releasable adhesive disposed on peripheral portions of the flat top surface of bottom support plate to facilitate fixation of the facing surface of the thinned wafer to the bottom support plate. 
     
     
         11 . The wafer carrier as defined in  claim 1 , wherein the wafer carrier is configured to support thinned wafers having a thickness no greater than 100 μm. 
     
     
         12 . The wafer carrier as defined in  claim 1 , wherein the holding ring is magnetized to releasably adhere to the bottom support plate, providing additional fixation between the bottom support plate and the holding ring, securing a placement of the thinned wafer therebetween. 
     
     
         13 . The wafer carrier as defined in  claim 1 , wherein the holding ring is formed of a material that allows expansion/contraction of the thinned wafer in the direction of the wafer surface, accommodating release of thermal stresses associated with coefficient of thermal expansion (CTE) between different layers forming the thinned wafer.