Temprature compensated chemical mechanical polishing apparatus and method

Abstract

A chemical mechanical polishing (CMP) system ( 22 ) having a radiant heating apparatus ( 30 ) for direct radiant heating of the polishing surface ( 26 ) of the polishing pad ( 16 ). Radiant energy ( 28 ) is impinged onto a selected area of the polishing surface to provide temperature compensation of the material removal rate across the surface ( 24 ) of the wafer ( 14 ). The radiant energy may be in the form of infrared radiation, a laser beam or microwave energy. The power level, angle of impingement, duration of exposure and footprint of the radiant energy may be controlled to achieve a desired temperature gradient on the polishing surface. The temperature of the polishing surface may further be regulated by impinging a temperature conditioning gas ( 32 ) onto the polishing surface.

I claim as my invention:  
     
         1 . A device for polishing a wafer, the device comprising: 
 a polishing pad having a polishing surface;    a wafer carrier adapted to urge a surface of a wafer against the polishing surface; and    a radiant heating apparatus positionable to provide radiant energy onto the polishing surface remote from the surface of the wafer.    
     
     
         2 . The device of  claim 1 , wherein the radiant heating apparatus comprises a source of infrared radiation.  
     
     
         3 . The device of  claim 1 , wherein the radiant heating apparatus comprises a laser.  
     
     
         4 . The device of  claim 1 , wherein the radiant heating apparatus comprises a source of microwave energy.  
     
     
         5 . The device of  claim 1 , wherein the radiant heating apparatus is disposed in a predetermined position with respect to the polishing surface to establish a predetermined radiant energy footprint on the polishing surface.  
     
     
         6 . A device for polishing a wafer, the device comprising: 
 a polishing pad having a polishing surface;    a wafer carrier adapted to urge a surface of a wafer against the polishing surface; and    a means for applying heat energy directly to the polishing surface from a source remote from the surface of the wafer.    
     
     
         7 . The device of  claim 6 , wherein the means for applying heat energy further comprises a flow of a temperature conditioning gas directed onto the polishing surface.  
     
     
         8 . The device of  claim 7 , wherein the flow of temperature conditioning gas is provided at a temperature greater than a temperature of the polishing surface.  
     
     
         9 . The device of  claim 7 , wherein the flow of temperature conditioning gas is provided at a temperature less than a temperature of the polishing surface.  
     
     
         10 . The device of  claim 7 , further comprising a radiant heating apparatus impinging radiant energy onto the polishing surface remote from the surface of the wafer.  
     
     
         11 . A method of polishing a wafer, the method comprising: 
 providing a polishing pad having a polishing surface;    urging a wafer surface against the polishing surface while providing relative motion there between; and    impinging the polishing surface with radiant energy at a location remote from the wafer surface to regulate a polishing surface temperature.    
     
     
         12 . The method of  claim 11 , further comprising varying an intensity of the radiant energy during the step of impinging.  
     
     
         13 . The method of  claim 11 , further comprising impinging the at least a portion of the polishing surface with radiant energy prior to the step of urging.  
     
     
         14 . The method of  claim 11 , further comprising impinging the at least a portion of the polishing surface with radiant energy during the step of urging.  
     
     
         15 . The method of  claim 11 , wherein the step of impinging further comprises exposing the at least a portion of the polishing surface to infrared radiation.  
     
     
         16 . The method of  claim 11 , wherein the step of impinging further comprises exposing the at least a portion of the polishing surface to laser energy.  
     
     
         17 . The method of  claim 11 , wherein the step of impinging further comprises exposing the at least a portion of the polishing surface to microwave energy.  
     
     
         18 . The method of  claim 11 , further comprising disposing a source of radiant energy at a predetermined position in relation to the polishing surface in order to establish a predetermined radiant energy footprint on the polishing surface.  
     
     
         19 . A method of polishing a wafer, the method comprising: 
 providing a polishing pad having a polishing surface;    urging a wafer surface against the polishing surface while providing relative motion there between; and    impinging the polishing surface with at least one of radiant energy and a temperature conditioning gas remote from the wafer surface to regulate a polishing surface temperature.    
     
     
         20 . The method of  claim 19 , further comprising impinging only an edge portion of the polishing surface with the at least one of radiant energy and a temperature conditioning gas.