Temperature endpointing of chemical mechanical polishing

Abstract

A method is described for temperature endpointing of a CMP process. A temperature sensor ( 110 ) detects temperature changes when the CMP polishing process transitions between different materials.

We claim:  
     
         1 . A method for detecting the end point of a chemical mechanical polishing process comprising: 
 providing a semiconductor substrate with a top film of a first material overlying a second film of a second material;    monitoring temperature of a polishing pad during a chemical mechanical polishing of said top film of said first material; and    stopping said chemical mechanical polishing upon detecting a non random change in temperature of said polishing pad as said chemical mechanical polishing transitions from said top film of said first material to said second film of said second material.    
     
     
         2 . The method of  claim 1  wherein said top film is a metal.  
     
     
         3 . The method of  claim 1  wherein said second film is a dielectric.  
     
     
         4 . The method of  claim 1  wherein said monitoring temperature of said polishing pad is performed using an infrared detector.  
     
     
         5 . The method of  claim 1  wherein said top film is a metal selected from the group consisting of tungsten and copper.  
     
     
         6 . The method of  claim 5  wherein said second film is silicon dioxide.  
     
     
         7 . The method of  claim 1  wherein said top film is silicon oxide.  
     
     
         8 . The method of  claim 7  wherein said second film is silicon nitride.  
     
     
         9 . A method for detecting the end point of a chemical mechanical polishing process comprising: 
 providing a semiconductor substrate with a top film of a first material overlying a second film of a second material;    monitoring temperature of a slurry during a chemical mechanical polishing of said top film of said first material; and    stopping said chemical mechanical polishing upon detecting a non random change in temperature of said slurry as said chemical mechanical polishing transitions from said top film of said first material to said second film of said second material.    
     
     
         10 . The method of  claim 9  wherein said top film is a metal.  
     
     
         11 . The method of  claim 10  wherein said second film is a dielectric.  
     
     
         12 . The method of  claim 9  wherein said monitoring temperature of said polishing pad is performed using an infrared detector.  
     
     
         13 . The method of  claim 9  wherein said top film is selected from the group consisting of tungsten and copper.  
     
     
         14 . The method of  claim 13  wherein said second film is selected from the group consisting of silicon dioxide and silicon nitride.  
     
     
         15 . A method for detecting the end point of a chemical mechanical polishing process comprising: 
 providing a semiconductor substrate with a plurality of films;    monitoring temperature of a polishing pad during a chemical mechanical polishing of said plurality of films; and    stopping said chemical mechanical polishing upon detecting a non random change in temperature of said polishing pad as said chemical mechanical polishing transitions from a first material film of said plurality of films to a second material film of said plurality of films.    
     
     
         16 . The method of  claim 15  wherein said plurality of films is formed from material from the group consisting of tungsten, silicon dioxide, copper, silicon nitride, and silicon.  
     
     
         17 . The method of  claim 15  wherein said monitoring temperature of said polishing pad is performed using an infrared detector.