Wafer transfer device for chemical mechanical polishing apparatus

Abstract

A wafer-transfer device for a chemical-mechanical polishing apparatus includes a base and lifting frame. A first cylinder is connected to a lower portion of the lifting frame to lift it and includes a piston rod passing through the lower portion of the lifting frame and fixed to the base. A basin-shaped contraposition ring is mounted onto an upper portion of the lifting frame via a spring. An inner edge of a top of the contraposition ring defines a curved surface adapted to a contour of a polishing head of the chemical-mechanical polishing apparatus. A wafer support is disposed above the contraposition ring. A second cylinder is mounted onto the contraposition ring and includes a piston rod passing through the contraposition ring and connected to a bottom of the wafer support to lift it. Respective axes of the wafer support, second cylinder, and contraposition ring coincide with one another.

What is claimed is: 
     
         1 . A wafer-transfer device for a chemical-mechanical polishing apparatus, said device comprising:
 a base;   a lifting frame;   at least one first cylinder connected to a lower portion of said lifting frame to lift said lifting frame and including a piston rod passing through said lower portion of said lifting frame and fixed to said base;   a basin-shaped contraposition ring mounted onto an upper portion of said lifting frame via at least one spring, an inner edge of a top of said contraposition ring defining a curved surface adapted to a contour of a polishing head of the chemical-mechanical polishing apparatus;   a wafer support disposed above said contraposition ring; and   a second cylinder mounted onto said contraposition ring and including a piston rod passing through said contraposition ring and connected to a bottom of said wafer support to lift said wafer support, wherein an axis of said wafer support, an axis of said second cylinder, and an axis of said contraposition ring coincide with one another.   
     
     
         2 . A wafer-transfer device as set forth in  claim 1 , wherein said upper portion of said lifting frame is formed with a side wall surrounding said contraposition ring and being substantially perpendicular to said upper portion of said lifting frame. 
     
     
         3 . A wafer-transfer device as set forth in  claim 1 , wherein said device comprises further at least one guiding shaft including a first end fixed to said base and a second end passing through said lower portion of said lifting frame and at least one linear bearing fitted over said guiding shaft, fixed to said lower portion of said lifting frame, and defining an axis of said linear bearing that is substantially parallel to said axis of said wafer support. 
     
     
         4 . A wafer-transfer device as set forth in  claim 1 , wherein said device comprises further at least one screw that passes through a corresponding through-hole formed in said contraposition ring and spring and is screwed into a corresponding screw-hole formed in said upper portion of said lifting frame. 
     
     
         5 . A wafer-transfer device as set forth in  claim 4 , wherein said device comprises further at least one cover plate for covering a top of corresponding said through-hole in said contraposition ring. 
     
     
         6 . A wafer-transfer device as set forth in  claim 5 , wherein a plurality of screws, cover plates, and springs are arranged on said upper portion of said lifting frame along a circumferential direction of said lifting frame at substantially equal respective intervals. 
     
     
         7 . A wafer-transfer device as set forth in  claim 1 , wherein said device comprises further a plurality of hydraulic buffers mounted onto said lower portion of said lifting frame, arranged on said lower portion of said lifting frame along a circumferential direction of said lifting frame at substantially equal intervals, and located below said base. 
     
     
         8 . A wafer-transfer device as set forth in  claim 1 , wherein a chamber is defined in said lifting frame and a portion of said second cylinder is located in said chamber. 
     
     
         9 . A wafer-transfer device as set forth in  claim 3 , wherein a plurality of first cylinders are arranged on said lower portion of said lifting frame along a circumferential direction of said lifting frame at substantially equal intervals and a plurality of linear bearings and guiding shafts are arranged on said lower portion of said lifting frame along said circumferential direction at substantially equal respective intervals. 
     
     
         10 . A wafer-transfer device as set forth in  claim 1 , wherein said lifting frame is substantially hollow and I-shaped.