Temperature control of chemical mechanical polishing

Abstract

A chemical mechanical polishing apparatus includes a platen to hold a polishing pad, a carrier to hold a substrate against a polishing surface of the polishing pad during a polishing process, a dispenser to supply a polishing liquid to the polishing surface, and a temperature control system including a body configured to contact the polishing surface or the polishing liquid on the polishing surface. The body supports a thermal control module positioned over the polishing pad.

What is claimed is: 
     
         1 . A chemical mechanical polishing apparatus comprising:
 a platen to hold a polishing pad;   a carrier to hold a substrate against a polishing surface of the polishing pad during a polishing process;   a dispenser to supply a polishing liquid to the polishing surface;   a temperature control system including a thermal control module positioned over the polishing pad and laterally spaced from the dispenser; and   a surface thermally coupled to the thermal control module, the surface suspended over the polishing pad and positioned to contact the polishing liquid on the polishing pad but be spaced from the polishing surface of the polishing pad.   
     
     
         2 . The apparatus of  claim 1 , comprising a body to support the thermal control module, wherein a portion of the body provides the surface and serves to thermally conduct heat between the polishing liquid and the temperature control module. 
     
     
         3 . The apparatus of  claim 2 , wherein at least a portion of the body that contacts the polishing liquid comprises a ceramic. 
     
     
         4 . The apparatus of  claim 2 , wherein at least a portion of the body that contacts the polishing liquid comprises silicon carbide, silicon nitride aluminum nitride, diamond or diamond-like carbon. 
     
     
         5 . The apparatus of  claim 1 , wherein a lower surface of the thermal control module provides the surface. 
     
     
         6 . The apparatus of  claim 1 , wherein the thermal control module comprises a stack including a thermoelectric heat pump and a heat exchanger. 
     
     
         7 . The apparatus of  claim 6 , wherein the heat exchanger is above the thermoelectric heat pump. 
     
     
         8 . The apparatus of  claim 1 , wherein the thermal control module comprises a stack including a resistive heater and a heat exchanger. 
     
     
         9 . A chemical mechanical polishing apparatus comprising:
 a platen to hold a polishing pad;   a carrier to hold a substrate against a polishing surface of the polishing pad during a polishing process;   a dispenser to supply a polishing liquid to the polishing surface;   a temperature control system including a thermal control module positioned over the polishing pad and laterally spaced from the dispenser, wherein the thermal control module comprises a stack including a thermoelectric heat pump and a heat exchanger;   a surface thermally coupled to the thermal control module, the surface suspended over the polishing pad and positioned to contact the polishing pad;   a temperature sensor to measure a temperature of the polishing pad; and   a controller configured to receive a temperature measurement from the temperature sensor and to perform pulse-width modulation of activation of the thermoelectric heat pump to move the temperature of the polishing pad toward a desired temperature.   
     
     
         10 . The apparatus of  claim 9 , comprising a body to support the thermal control module, wherein a portion of the body provides the surface and serves to thermally conduct heat between the polishing liquid and the temperature control module. 
     
     
         11 . The apparatus of  claim 9 , wherein a lower surface of the thermal control module provides the surface. 
     
     
         12 . The apparatus of  claim 9 , wherein the controller is configured to control a temperature or flow rate of fluid passing through the heat exchanger to cause the heat exchanger to raise or lower a temperature of a top surface of the thermoelectric heat pump. 
     
     
         13 . A chemical mechanical polishing apparatus comprising:
 a platen to hold a polishing pad;   a carrier to hold a substrate against a polishing surface of the polishing pad during a polishing process;   a dispenser to supply a polishing liquid to the polishing surface;   a temperature control system including a thermal control module positioned over the polishing pad and laterally spaced from the dispenser, wherein the thermal control module comprises a stack including a resistive heater and a heat exchanger;   a surface thermally coupled to the thermal control module, the surface suspended over the polishing pad and positioned to contact the polishing pad;   a temperature sensor to measure a temperature of the polishing pad; and   a controller configured to receive a temperature measurement from the temperature sensor and to perform pulse-width modulation of activation of the resistive heater to move the temperature of the polishing pad toward a desired temperature.   
     
     
         14 . The apparatus of  claim 13 , comprising a body to support the thermal control module, wherein a portion of the body provides the surface and serves to thermally conduct heat between the polishing liquid and the temperature control module. 
     
     
         15 . The apparatus of  claim 13 , wherein a lower surface of the thermal control module provides the surface. 
     
     
         16 . The apparatus of  claim 13 , wherein the controller is configured to control a temperature or flow rate of fluid passing through the heat exchanger to cause the heat exchanger to raise or lower a temperature of a top surface of the resistive heater.