Substrate Polishing Method and Apparatus

Abstract

A polishing apparatus is provided for optimizing a polishing profile in consideration of even such parameters as the temperature on the surface of an object to be polished, and the thickness of a polishing pad, in addition to a polished amount. The polishing apparatus for polishing the object to be polished under control of a control unit CU has at least two pressing sections, and comprises a top ring which can apply an arbitrary pressure to the object to be polished from each of the pressing sections, a measuring device IM for measuring a polished amount of the object to be polished, and a monitoring device SM for monitoring the object to be polished for a polishing condition. The control unit CU forces the polishing apparatus to polish the object to be polished in accordance with a simulation program for setting processing pressures required to optimize a polishing profile of the object to be polished to the top ring based on the output of the measuring device IM and the output of the monitoring device SM.

1 . A polishing apparatus for polishing an object to be polished under control of a control unit, comprising:
 a top ring having at least two pressing sections and capable of applying an arbitrary pressure to the object to be polished from each of said pressing sections;   a measuring device for measuring a polished amount of the object to be polished; and   a monitoring device for monitoring the object to be polished for a polishing state, said polishing apparatus characterized in that:   said control unit forces said polishing apparatus to polish the object to be polished in accordance with a simulation program for setting a processing pressure required to optimize a polishing profile of the object to be polished to said top ring based on the output of said measuring device and the output of said monitoring device.   
     
     
         2 . A polishing apparatus according to  claim 1 , characterized in that:
 said at least two pressing sections include a plurality of concentric air bags, and a retainer ring surrounding said air bags, and   the pressure of said retainer ring is kept at a value larger by 20 percent than an average value of the sum total of the pressures applied by said air bags.   
     
     
         3 . A polishing apparatus according to  claim 1 , further comprising a polishing pad for polishing the object to be polished such that said pad is depressed by said top ring, wherein said control unit instructs said polishing apparatus to polish a monitor wafer instead of the object when said monitoring device detects that said polishing pad is cut away by a predetermined depth. 
     
     
         4 . A polishing apparatus according to  claim 2 , characterized in that when the output of said monitoring device indicates that an abrasion loss of said retainer ring falls below a threshold, said control unit instructs said polishing apparatus to stop polishing. 
     
     
         5 . A polishing apparatus according to  claim 1 , characterized in that:
 when the output of said monitoring device indicates that the temperature on the surface of the object to be polished exceeds a predetermined set temperature, said control unit stops using the simulation program or instructs said polishing apparatus to stop polishing, and   when the output of said monitoring device indicates that the temperature on the surface falls below the set temperature, said control unit instructs said polishing apparatus to resume the polishing.   
     
     
         6 . A polishing apparatus according to  claim 1 , further comprising a polishing pad for polishing the object to be polished in a state in which said polishing pad is pressed against the object to be polished by said top ring, said polishing apparatus characterized in that:
 when the output of said monitoring device indicates that the thickness of said polishing pad falls below a threshold, said control unit stops using the simulation program or instructs said polishing apparatus to stop polishing.   
     
     
         7 . A polishing apparatus according to  claim 6 , characterized in that said monitoring device comprises a laser displacement gage for measuring the thickness of said polishing pad. 
     
     
         8 . A polishing apparatus according to  claim 1 , further comprising a polishing pad for polishing the object to be polished in a state in which said polishing pad is pressed against the object to be polished by said top ring, and a dresser for conditioning said polishing pad, said polishing apparatus characterized in that:
 when the output of said monitoring device indicates that a cutting rate of said dresser falls below a threshold, said control unit stops using the simulation program, or instructs said polishing apparatus to stop polishing.   
     
     
         9 . A polishing apparatus according to  claim 7 , characterized in that the cutting rate is monitored using a torque of a motor for driving said dresser. 
     
     
         10 . A polishing apparatus according to  claim 1 , characterized in that said control unit can adjust the amount of supplied slurry in accordance with the polishing state. 
     
     
         11 . A polishing apparatus according to  claim 2 , further comprising a polishing pad for polishing the object to be polished such that said pad is depressed by said top ring, wherein said control unit instructs said polishing apparatus to polish a monitor wafer instead of the object when said monitoring device detects that said polishing pad is cut away by a predetermined depth. 
     
     
         12 . A polishing apparatus according to  claim 2 , characterized in that:
 when the output of said monitoring device indicates that the temperature on the surface of the object to be polished exceeds a predetermined set temperature, said control unit stops using the simulation program or instructs said polishing apparatus to stop polishing, and   when the output of said monitoring device indicates that the temperature on the surface falls below the set temperature, said control unit instructs said polishing apparatus to resume the polishing.   
     
     
         13 . A polishing apparatus according to  claim 2 , further comprising a polishing pad for polishing the object to be polished in a state in which said polishing pad is pressed against the object to be polished by said top ring, said polishing apparatus characterized in that:
 when the output of said monitoring device indicates that the thickness of said polishing pad falls below a threshold, said control unit stops using the simulation program or instructs said polishing apparatus to stop polishing.   
     
     
         14 . A polishing apparatus according to  claim 2 , further comprising a polishing pad for polishing the object to be polished in a state in which said polishing pad is pressed against the object to be polished by said top ring, and a dresser for conditioning said polishing pad, said polishing apparatus characterized in that:
 when the output of said monitoring device indicates that a cutting rate of said dresser falls below a threshold, said control unit stops using the simulation program, or instructs said polishing apparatus to stop polishing.   
     
     
         15 . A polishing apparatus according to  claim 2 , characterized in that said control unit can adjust the amount of supplied slurry in accordance with the polishing state. 
     
     
         16 . A polishing apparatus according to  claim 3 , characterized in that said control unit can adjust the amount of supplied slurry in accordance with the polishing state. 
     
     
         17 . A polishing apparatus according to  claim 4 , characterized in that said control unit can adjust the amount of supplied slurry in accordance with the polishing state. 
     
     
         18 . A polishing apparatus according to  claim 5 , characterized in that said control unit can adjust the amount of supplied slurry in accordance with the polishing state. 
     
     
         19 . A polishing apparatus according to  claim 6 , characterized in that said control unit can adjust the amount of supplied slurry in accordance with the polishing state. 
     
     
         20 . A polishing apparatus according to  claim 7 , characterized in that said control unit can adjust the amount of supplied slurry in accordance with the polishing state.