Temperature control with intra-layer transition during cmp

Abstract

A method for removing material from a substrate includes dispensing an abrasive slurry on a polishing pad, storing an indication of a relative charge on the abrasive agent, contacting a surface of a substrate to the polishing pad in the presence of the slurry, generating relative motion between the substrate and the polishing pad, measuring a removal rate for the substrate, comparing a the measured removal rate to a target removal rate and determining whether to increase or decrease the removal rate based on the comparison, determining whether to increase or decrease a temperature of an interface between the polishing pad and the substrate based on the indication of the relative charge of the abrasive agent and on whether to increase or decrease the removal rate, and controlling a temperature of the interface as determined to modify the removal rate.

What is claimed is: 
     
         1 . A method of polishing, comprising:
 polishing a layer on a substrate by dispensing a polishing slurry onto a polishing pad, contacting a surface of the layer on the substrate to the polishing pad in the presence of the slurry, and generating relative motion between the substrate and the polishing pad;   for an initial portion of polishing of the layer, controlling temperature of the polishing to be within a first temperature range;   obtaining a temperature transition time that is before an endpoint time;   upon determining that the temperature transition time is reached, lowering the temperature of the polishing to be within a lower second temperature range that is lower than the first temperature range; and   for a subsequent portion of polishing of the same layer, controlling temperature of the polishing to be within the second temperature range until the estimated endpoint time.   
     
     
         2 . The method of  claim 1 , wherein the polishing slurry comprises silica abrasive particles or positively charged ceria particles. 
     
     
         3 . The method of  claim 1 , wherein decreasing the temperature comprises dispensing a coolant fluid onto the polishing pad. 
     
     
         4 . The method of  claim 1 , wherein the surface of the substrate comprises an oxide layer. 
     
     
         5 . The method of  claim 4 , wherein the oxide layer comprises silicon oxide. 
     
     
         6 . The method of  claim 1 , wherein obtaining the temperature transition time comprises storing a predetermined transition time. 
     
     
         7 . The method of  claim 1 , wherein obtaining the temperature transition time comprises calculating the temperature transition time based on an expected endpoint time. 
     
     
         8 . The method of  claim 7 , comprising monitoring the substrate during polishing with an in-situ monitoring system and determining the expected endpoint time based on a signal from the in-situ monitoring system. 
     
     
         9 . The method of  claim 7 , wherein calculating the temperature transition time comprises subtracting a predetermined period from the expected endpoint. 
     
     
         10 . The method of  claim 7 , wherein calculating the temperature transition time comprises subtracting a percentage of a total polishing time from the expected endpoint time. 
     
     
         11 . A method of polishing, comprising:
 polishing a layer on a substrate by dispensing a polishing slurry onto a polishing pad, contacting a surface of the layer on a substrate to the polishing pad in the presence of the slurry, and generating relative motion between the substrate and the polishing pad;   for an initial portion of polishing of the layer, controlling temperature of the polishing to be within a first temperature range;   determining a temperature transition time that is before an endpoint time;   upon determining that the temperature transition time is reached, increasing pressure on the substrate while increasing coolant flow to continue to maintain the temperature of the polishing to be within the first temperature range; and   for a subsequent portion of polishing of the same layer, maintaining the increased pressure and controlling temperature of the polishing to be within the first temperature range until the estimated endpoint time.   
     
     
         12 . The method of  claim 11 , wherein the polishing slurry comprises silica abrasive particles or positively charged ceria particles. 
     
     
         13 . The method of  claim 11 , wherein decreasing the temperature comprises dispensing a coolant fluid onto the polishing pad. 
     
     
         14 . The method of  claim 11 , wherein the surface of the substrate comprises an oxide layer. 
     
     
         15 . The method of  claim 14 , wherein the oxide layer comprises silicon oxide. 
     
     
         16 . The method of  claim 11 , wherein obtaining the temperature transition time comprises storing a predetermined transition time. 
     
     
         17 . The method of  claim 11 , wherein obtaining the temperature transition time comprises calculating the temperature transition time based on an expected endpoint time. 
     
     
         18 . The method of  claim 17 , comprising monitoring the substrate during polishing with an in-situ monitoring system and determining the expected endpoint time based on a signal from the in-situ monitoring system. 
     
     
         19 . The method of  claim 17 , wherein calculating the temperature transition time comprises subtracting a predetermined period from the expected endpoint. 
     
     
         20 . The method of  claim 17 , wherein calculating the temperature transition time comprises subtracting a percentage of a total polishing time from the expected endpoint time.