Polishing apparatus and method for controlling polishing apparatus

Abstract

A polishing apparatus is controlled to perform dressing at appropriate timing. A controller of the polishing apparatus determines, based on the state of a polishing surface of a polishing pad measured by a measurement device, estimated timing when the degree of polishing capability of the polishing pad is expected to be fallen below a threshold level; identifies, from multiple free time slots in an operation schedule, a free time slot positioned just before the estimated timing; and makes a dressing device apply a dressing process to the polishing pad in the identified free time slot.

What is claimed is: 
     
         1 . A polishing apparatus comprising:
 one or multiple polishing units,   one or multiple functional units for performing preprocessing or postprocessing of polishing,   one or multiple transfer units for carrying, at least between the polishing unit and the functional unit, an object of polishing, and   a controller for performing control to make the polishing unit, the functional unit, and the transfer unit operate in accordance with a predetermined operation schedule for performing polishing of the object of polishing, wherein the operation schedule comprises multiple free time slots during that the polishing unit is not allowed to perform processing due to restriction relating to relationship between operation of the polishing unit, operation of the functional unit, and operation of the transfer unit;   wherein   each of the one or multiple polishing units comprises   a polishing pad constructed to be pressed against the object of polishing when the object of polishing is polished,   a measurement device for measuring a state of a polishing surface of the polishing pad, and   a dressing device constructed to apply a dressing process to the polishing pad; and   wherein   the controller is constructed to   determine, based on the state of the polishing surface of the polishing pad measured by the measurement device, estimated timing when the degree of polishing capability of the polishing pad is expected to be fallen below a threshold level,   identify, from the multiple free time slots in the operation schedule, a free time slot positioned just before the estimated timing, and   make the dressing device perform the dressing process applied to the polishing pad in the identified free time slot.   
     
     
         2 . The polishing apparatus as recited in  claim 1 , wherein determination of the timing is based on extrapolation applied to an index representing the state of the polishing surface of the polishing pad. 
     
     
         3 . The polishing apparatus as recited in  claim 1 , wherein the controller is constructed to make, with respect to each of the multiple free time slots in the operation schedule and by performing extrapolation, an estimate as to whether the degree of polishing capability of the polishing pad falls below the threshold level; and, if the estimate shows that the degree of polishing capability falls below the threshold level, make the dressing device apply the dressing process to the polishing pad in the free time slot. 
     
     
         4 . The polishing apparatus as recited in  claim 1 , wherein the functional unit comprises a cleaning unit for washing the object of polishing after it is polished by the polishing unit. 
     
     
         5 . The polishing apparatus as recited in  claim 1 , wherein the controller is further constructed to create the predetermined operation schedule based on predetermined recipe information. 
     
     
         6 . A polishing apparatus comprising:
 one or multiple polishing units,   one or multiple functional units for performing preprocessing or postprocessing of polishing,   one or multiple transfer units for carrying, at least between the polishing unit and the functional unit, an object of polishing, and   a controller for performing control to make the polishing unit, the functional unit, and the transfer unit operate in accordance with a predetermined operation schedule for performing polishing of the object of polishing, wherein the operation schedule comprises multiple free time slots during that the polishing unit is not allowed to perform processing due to restriction relating to relationship between operation of the polishing unit, operation of the functional unit, and operation of the transfer unit;   wherein   each of the one or multiple polishing units comprises   a polishing pad constructed to be pressed against the object of polishing when the object of polishing is polished, and   a dressing device constructed to apply a dressing process to the polishing pad; and   wherein   the controller is constructed to make the dressing device perform the dressing process applied to the polishing pad in each of the multiple free time slots.   
     
     
         7 . A method for controlling a polishing apparatus, wherein the polishing apparatus comprises:
 one or multiple polishing units,   one or multiple functional units for performing preprocessing or postprocessing of polishing,   one or multiple transfer units for carrying, at least between the polishing unit and the functional unit, an object of polishing, and   a controller for performing control to make the polishing unit, the functional unit, and the transfer unit operate in accordance with a predetermined operation schedule for performing polishing of the object of polishing, wherein the operation schedule comprises multiple free time slots during that the polishing unit is not allowed to perform processing due to restriction relating to relationship between operation of the polishing unit, operation of the functional unit, and operation of the transfer unit;   wherein   each of the one or multiple polishing units comprises   a polishing pad constructed to be pressed against the object of polishing when the object of polishing is polished,   a measurement device for measuring a state of a polishing surface of the polishing pad, and   a dressing device constructed to apply a dressing process to the polishing pad: and   the method comprises steps for   determining, by the controller and based on the state of the polishing surface of the polishing pad measured by the measurement device, estimated timing when the degree of polishing capability of the polishing pad is expected to be fallen below a threshold level,   identifying, by the controller and from the multiple free time slots in the operation schedule, a free time slot positioned just before the estimated timing, and   making, by the controller, the dressing device perform the dressing process applied to the polishing pad in the identified free time slot.   
     
     
         8 . A method for controlling a polishing apparatus, wherein the polishing apparatus comprises:
 one or multiple polishing units,   one or multiple functional units for performing preprocessing or postprocessing of polishing,   one or multiple transfer units for carrying, at least between the polishing unit and the functional unit, an object of polishing, and   a controller for performing control to make the polishing unit, the functional unit, and the transfer unit operate in accordance with a predetermined operation schedule for performing polishing of the object of polishing, wherein the operation schedule comprises multiple free time slots during that the polishing unit is not allowed to perform processing due to restriction relating to relationship between operation of the polishing unit, operation of the functional unit, and operation of the transfer unit;   wherein   each of the one or multiple polishing units comprises   a polishing pad constructed to be pressed against the object of polishing when the object of polishing is polished, and   a dressing device constructed to apply a dressing process to the polishing pad: and   the method comprises a step performed by the controller for making the dressing device perform the dressing process applied to the polishing pad in each of the multiple free time slots.