Polishing method and polishing apparatus

Abstract

A polishing method polishes a surface (surface to be polished) of a substrate at a sufficient polishing rate and obtains a desired polishing profile while preventing an unpolished portion from remaining on the surface of the substrate after polishing. The polishing method polishes a surface to be polished with a polishing pad while controlling the temperature of the polishing pad by blowing a gas toward the polishing pad. The polishing method includes monitoring the polishing state of the substrate to be polished during polishing while PID-controlling the flow rate or the blow direction of the gas, and changing the control temperature of the polishing pad when a predetermined thickness of a film to be polished is reached.

1 . A polishing method for polishing a surface to be polished with a polishing pad while controlling the temperature of the polishing pad by blowing a gas toward the polishing pad, said method comprising:
 monitoring the polishing state of the surface to be polished during polishing while PID-controlling the flow rate or the blow direction of the gas; and   changing the control temperature of the polishing pad when a predetermined thickness of a film to be polished is reached.   
     
     
         2 . The polishing method according to  claim 1 , wherein a dry gas is used as the gas before the predetermined film thickness is reached, and a mist is used as the gas after the predetermined film thickness is reached. 
     
     
         3 . The polishing method according to  claim 1 , wherein polishing is carried out at a first polishing pressure before the predetermined film thickness is reached and, after the predetermined film thickness is reached, polishing is carried out at a second polishing pressure which is lower than the first polishing pressure. 
     
     
         4 . The polishing method according to  claim 1 , wherein the monitoring of the surface to be polished during polishing is performed by using an eddy current sensor, an optical sensor or a torque current sensor. 
     
     
         5 . A polishing method for polishing a surface to be polished with a polishing pad while controlling the temperature of the polishing pad by blowing a gas toward the polishing pad, said method comprising:
 a first polishing step of polishing the surface to be polished while controlling the temperature of the polishing pad at a temperature corresponding to that elastic modulus of the polishing pad which achieves the maximum polishing rate, based on data on a correlation between the elastic modulus of the polishing pad and the temperature of the polishing pad as well as data on a correlation between the elastic modulus of the polishing pad and the polishing rate or data on a correlation between the elastic modulus of the polishing pad and at least one of the planarities, the number of defects and the amount of unpolished metal; and   a second polishing step of polishing the surface to be polished while controlling, based on the correlation data, the temperature of the polishing pad at a temperature corresponding to that elastic modulus of the polishing pad which achieves desired planarities.   
     
     
         6 . A polishing method for polishing a surface to be polished with a polishing pad while controlling the temperature of the polishing pad by blowing a gas toward the polishing pad, said method comprising:
 monitoring the polishing state of the surface to be polished during polishing and, when a predetermined thickness of a film to be polished is reached, predicting a polishing end time; and   controlling the blowing of the gas so that the temperature of the polishing pad reaches a predetermined temperature at the polishing end time.   
     
     
         7 . A polishing apparatus for polishing a substrate comprising:
 a gas blow section for blowing a gas toward a polishing pad to control the temperature of the polishing pad;   a controller for PID-controlling the flow rate or the blow direction of the gas blown from the gas blow section; and   a monitor for monitoring the polishing state of a surface to be polished,   wherein a recipe, which indicates a relationship between the control temperature of the polishing pad and the thickness of a film to be polished, is stored in the controller, and   wherein the controller and the monitor are configured to operate based on the recipe and change the control temperature of the polishing pad according to the thickness of the film.   
     
     
         8 . The polishing apparatus according to  claim 7 , further comprising:
 a cleaning tool for cleaning the gas blow section.   
     
     
         9 . The polishing apparatus according to  claim 7 , wherein the gas blow section is comprised of at least one of a cooling nozzle for blowing the dry gas toward the polishing pad and a cooling fan for blowing the dry gas toward the polishing pad. 
     
     
         10 . The polishing apparatus according to  claim 7 , further comprising:
 a temperature sensor for detecting the temperature of the polishing pad; and   a temperature controller for controlling, based on a detection value of the temperature sensor, an amount of the dry gas to be supplied from the gas blow section to the polishing pad.   
     
     
         11 . A method for polishing a substrate by bringing the substrate into sliding contact with a polishing pad, said method comprising:
 rotating a polishing table holding the polishing pad;   pressing a surface of the substrate against the polishing pad;   supplying a slurry to the polishing pad;   blowing a gas toward the polishing pad while controlling a flow rate or a blow direction of the gas by PID-control so that a temperature of the polishing pad becomes a first control temperature;   monitoring a polishing state of the substrate; and   blowing a gas toward the polishing pad while controlling a flow rate or a blow direction of the gas by PID-control so that a temperature of the polishing pad becomes a second control temperature after the polishing state is detected to be a predetermined state.   
     
     
         12 . The polishing method according to  claim 11 , wherein a dry gas is used as the gas before the polishing state is detected to be the predetermined state, and a mist is used as the gas after the polishing state is detected to be the predetermined state. 
     
     
         13 . The polishing method according to  claim 11 , wherein polishing is carried out at a first polishing pressure before the polishing state is detected to be the predetermined state and, after the polishing state is detected to be the predetermined state, polishing is carried out at a second polishing pressure which is lower than the first polishing pressure. 
     
     
         14 . The polishing method according to  claim 11 , wherein the monitoring of the polishing state of the substrate is performed by using an eddy current sensor, an optical sensor or a torque current sensor.