Method of fabricating semiconductor device and polishing apparatus used therefor

Abstract

The present invention provides a method of fabricating a semiconductor device, which is capable of suitably polishing an interconnection metal layer by a CMP method and improving the throughput of a CMP apparatus, and a polishing apparatus used therefor. The polishing apparatus includes a relay unit, disposed between a polishing unit having a plurality of polishing portions and a transfer robot, for temporarily supporting a wafer, wherein the relay unit is provided with inspection means for evaluating a plane to be polished of the polished wafer. With this configuration, it is possible to evaluate polishing of an already polished wafer while continuing a polishing step for other wafers and hence to improve the productivity of the polishing apparatus. In the case of setting objects to be inspected by the inspection means to an in-plane separation width and a dishing amount of an interconnection layer formed by a Damascene process, it is possible to suitably evaluate polishing of the interconnection layer in consideration of dense and coarse interconnection pattern portions of the interconnection layer.

What is claimed is:  
     
         1 . A method of fabricating a semiconductor device, comprising: 
 a wafer preparation step of preparing a wafer on which an interconnection metal film is formed on an insulating film provided with interconnection grooves;    a polishing step of removing said interconnection metal film excluding portions thereof in said grooves by polishing, to form an interconnection layer composed of interconnection layer portions buried in said interconnection grooves; and    an inspection step of inspecting a state of a plane to be polished of said wafer;    wherein said inspection step further comprises: 
 a step of measuring an in-plane separation width between adjacent two of said interconnection layer portions; and  
 a step of measuring a dishing amount of said interconnection layer portion.  
   
     
     
         2 . A method of fabricating a semiconductor device according to  claim 1 , wherein said inspection step is performed in a specific chip region within a surface of said wafer.  
     
     
         3 . A method of fabricating a semiconductor device according to  claim 1 , wherein said inspection step for said wafer is performed during a period of time in which other wafers are polished in said polishing step.  
     
     
         4 . A method of fabricating a semiconductor device according to  claim 1 , wherein said metal film is made from copper.  
     
     
         5 . A polishing apparatus comprising: 
 a polishing unit having a plurality of polishing portions for polishing a layer to be polished formed on a surface of a wafer;    transfer means for transferring said wafer between said polishing unit and the same;    a relay unit, disposed between said polishing unit and said transfer unit, for temporarily supporting said wafer to be transferred; and    a carrier for circulating said wafer to said polishing portions and said relay unit;    wherein said relay unit is provided with inspection means for evaluating the plane to be polished of said polished wafer.    
     
     
         6 . A polishing apparatus according to  claim 5 , wherein said inspection means comprises: 
 an inspection stage for supporting said wafer; and    a measurement head, disposed opposite to the plane to be polished of said polished wafer, for optically detecting a state of the plane to be polished of said polished wafer.    
     
     
         7 . A polishing apparatus according  claim 6 , wherein said measurement head is movable in the direction parallel to the plane to be polished of said polished wafer.  
     
     
         8 . A polishing apparatus according to  claim 5 , further comprising control means for changing the setting of polishing conditions at said polishing portions on the basis of an inspection result by said inspecting means.