Polishing apparatus and polishing method

Abstract

A polishing apparatus capable of obtaining a desired film thickness profile is disclosed. The polishing apparatus includes: a polishing unit; a film thickness measuring device for measuring a film thickness profile of a substrate; and a controller for controlling at least operations of the polishing unit and the film thickness measuring device. The controller stores in advance a response model which is created by taking into consideration variation in an amount of polishing between monitored areas of the substrate due to variations in a pressure of a pressurized fluid supplied to each of pressure chambers. Further, the controller obtains a film thickness profile of the substrate before polishing by use of a film thickness measuring device, and causes the substrate to be polished with an optimized polishing recipe created based on the response model and a target polishing amount, which is a difference between the film thickness profile of the substrate before polishing and the target film thickness of the substrate. A next substrate is polished with a new optimized polishing recipe which is created based on a target polishing amount of the next substrate and a response model corrected by use of the optimized polishing recipe and film thickness profiles of the substrate before and after polishing.

What is claimed is: 
     
         1 . A polishing apparatus, comprising:
 at least one polishing unit including a polishing table for supporting a polishing pad, and a substrate holder for pressing a substrate against the polishing pad;   a film thickness measuring device configured to measure a film thickness profile of the substrate; and   a controller configured to control at least operations of the polishing unit and the film thickness measuring device,   wherein the substrate holder includes:
 an elastic membrane film to form a plurality of pressure chambers for pressing the substrate; 
 a head body to which the elastic membrane is attached; and 
 a retainer ring arranged so as to surround the substrate, 
   the controller
 stores in advance film thickness profiles of a plurality of substrates before polishing and response models for polishing each of the plurality of substrates, the response models being created by taking into consideration variation in the amount of polishing between monitored areas of the substrate due to variations in a pressure of each of the pressure chambers, and 
 classifies in advance the film thickness profiles of the plurality of substrates before polishing into a plurality of groups to which the film thickness profiles similar to each other belong, 
   the controller
 obtains a film thickness profile of the substrate before polishing by use of the film thickness measuring device, 
 determines a group, to which the film thickness profile of the substrate before polishing belongs, from the plurality of groups, 
 causes the substrate to be polished with an optimized polishing recipe including at least the pressures of the pressurized fluid supplied to each of the plurality of pressure chambers and the polishing time, the optimized polishing recipe being created based on a target polishing amount, which is a difference between the film thickness profile of the substrate before polishing and the target film thickness of the substrate, and a response model associated with the determined group, and 
 causes a next substrate to be polished with a new optimized polishing recipe which is created based on a target polishing amount of the next substrate, and a response model corrected by use of the optimized polishing recipe and film thickness profiles of the substrate before and after polishing. 
   
     
     
         2 . A polishing apparatus, comprising:
 a plurality of polishing units each including a polishing table for supporting a polishing pad, and a substrate holder for pressing a substrate against the polishing pad; and   a controller configured to control at least operation of the polishing units,   wherein the substrate holder includes:
 an elastic membrane film to form a plurality of pressure chambers for pressing the substrate; 
 a head body to which the elastic membrane is attached; and 
 a retainer ring arranged so as to surround the substrate, 
   the substrate is a substrate which is polished by a plurality of polishing processes including a first polishing and a second polishing performed in the polishing unit different from the polishing unit in which the first polishing has been performed,   the polishing unit in which the first polishing is performed has a film thickness sensor for measuring a film thickness profile of the substrate,   the controller stores in advance a response model for the second polishing which is created by taking into consideration variation in the amount of polishing between monitored areas of the substrate due to variations in a pressure of a pressurized fluid supplied to each of the pressure chambers, and   the controller
 obtains, after performing the first polishing, a film thickness profile of the substrate before the second polishing by use of the film thickness sensor, 
 causes the substrate to be second polished with an optimized polishing recipe for the second polishing including at least the pressures of the pressurized fluid supplied to each of the plurality of pressure chambers and the polishing time, the optimized polishing recipe being created based on a target polishing amount, which is a difference between the film thickness profile of the substrate before the second polishing and the target film thickness of the substrate, and the response model for the second polishing, and 
 causes a next substrate to be second polished with a new optimized polishing recipe for the second polishing which is created based on a target polishing amount of the next substrate, and a response model corrected by use of the optimized polishing recipe for the second polishing and film thickness profiles of the substrate before and after the second polishing. 
   
     
     
         3 . A polishing apparatus, comprising:
 at least one polishing unit including a polishing table for supporting a polishing pad, and a substrate holder for pressing a substrate against the polishing pad;   a film thickness measuring device configured to measure a film thickness profile of the substrate; and   a controller configured to control at least operations of the polishing unit and the film thickness measuring device,   wherein the substrate holder includes:
 an elastic membrane film to form a plurality of pressure chambers for pressing the substrate; 
 a head body to which the elastic membrane is attached; and 
 a retainer ring arranged so as to surround the substrate, 
   the substrate is a substrate which is polished by a plurality of polishing processes including a first polishing and a second polishing performed in the polishing unit different from the polishing unit in which the first polishing has been performed,   the polishing unit in which the second polishing is performed has a film thickness sensor for measuring a film thickness profile of the substrate,   the controller stores in advance a response model for the first polishing which is created by taking into consideration variation in the amount of polishing between monitored areas of the substrate due to variations in a pressure of a pressurized fluid supplied to each of the pressure chambers, and   the controller
 obtains a film thickness profile of the substrate before the first polishing by use of the film thickness sensor, 
 causes the substrate to be first polished with an optimized polishing recipe for the first polishing including at least the pressures of the pressurized fluid supplied to each of the plurality of pressure chambers and the polishing time, the optimized polishing recipe being created based on a target polishing amount, which is a difference between the film thickness profile of the substrate before the first polishing and the target film thickness of the substrate, and the response model for the first polishing, and 
 causes the substrate to be transferred, after performing the first polishing to the polishing unit having the film thickness sensor, to obtain a film thickness profile of the substrate after the first polishing by use of the film thickness sensor, and 
 causes a next wafer to be first polished with a new optimized polishing recipe for first polishing which is created based on a target polishing amount of the next substrate, and a response model corrected by use of the optimized polishing recipe for the first polishing and film thickness profiles of the substrate before and after the first polishing. 
   
     
     
         4 . A polishing apparatus, comprising:
 a plurality of polishing units each including a polishing table for supporting a polishing pad, a substrate holder for pressing a substrate against the polishing pad, and a film thickness sensor for measuring a film thickness profile of the substrate; and   a controller configured to control at least operation of the polishing units,   wherein the substrate holder includes:
 an elastic membrane film to form a plurality of pressure chambers for pressing the substrate; 
 a head body to which the elastic membrane is attached; and 
 a retainer ring arranged so as to surround the substrate, 
   the substrate is a substrate which is polished by a plurality of polishing processes including a first polishing and a second polishing performed in the polishing unit different from the polishing unit in which the first polishing has been performed,   the controller stores in advance a response model for the first polishing and a response model for the second polishing which is created by taking into consideration variation in the amount of polishing between monitored areas of the substrate due to variations in a pressure of a pressurized fluid supplied to each of the pressure chambers, and   the controller
 causes the substrate to be transferred to any one of the plurality of polishing units to obtain a film thickness profile of the substrate before the first polishing, 
 causes the substrate to be first polished with an optimized polishing recipe for the first polishing including at least the pressures of the pressurized fluid supplied to each of the plurality of pressure chambers and the polishing time, the optimized polishing recipe being created based on a target polishing amount, which is a difference between the film thickness profile of the substrate before the first polishing and the target film thickness of the substrate, and the response model for the first polishing, 
 obtains a film thickness profile of the substrate before the second polishing by use of the film thickness sensor, 
 causes the substrate to be second polished with an optimized polishing recipe for the second polishing including at least the pressures of the pressurized fluid supplied to each of the plurality of pressure chambers and the polishing time, the optimized polishing recipe being created based on a target polishing amount, which is a difference between the film thickness profile of the substrate before the second polishing and the target film thickness of the substrate, and the response model for the second polishing, and 
 obtains a film thickness profile of the substrate after the second polishing by use of film thickness sensor, 
 causes a next substrate to be polished with a new optimized polishing recipe for first polishing which is created based on a target polishing amount of the next substrate, and a response model corrected by use of the optimized polishing recipe for the first polishing and film thickness profiles of the substrate before and after the first polishing, 
 causes the next substrate to be second polished with a new optimized polishing recipe for the second polishing which is created based on a target polishing amount of the next substrate, and a response model corrected by use of the optimized polishing recipe for the second polishing and film thickness profiles of the substrate before and after the second polishing.