Index polishing for process control signal and wafer uniformity

Abstract

A method of performing polishing processes on substrates may include receiving a substrate in a known alignment in a carrier head of a polishing station for a polishing process. The polishing process may cause the substrate in the carrier head to be polished by a polishing pad on a platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths relative to the known alignment of the substrate. The method may also include causing the carrier head to move to a first position based on the one or more predetermined sensor paths; causing the platen to move to a second position based on the one or more predetermined sensor paths; and causing the substrate to rotate relative to the platen such that the one or more sensors pass along the one or more predetermined sensor paths.

What is claimed is: 
     
         1 . A method of performing polishing processes on substrates, the method comprising:
 receiving a substrate in a known alignment in a carrier head of a polishing station for a polishing process, wherein the polishing process causes the substrate in the carrier head to be polished by a polishing pad on a platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths relative to the known alignment of the substrate;   causing the carrier head to move to a first position based on the one or more predetermined sensor paths;   causing the platen to move to a second position based on the one or more predetermined sensor paths; and   causing the substrate to rotate relative to the platen such that the one or more sensors pass along the one or more predetermined sensor paths.   
     
     
         2 . The method of  claim 1 , wherein, one or more sensors to detect one or more attributes associated with the substrate that are indicative of a thickness that is being polished. 
     
     
         3 . The method of  claim 1 , further comprising:
 determining a first rotational speed associated with the platen based on the one or more predetermined sensor paths; and   determining a second rotational speed associated with the substrate based on the one or more predetermined sensor paths.   
     
     
         4 . The method of  claim 1 , wherein a groove of the polishing pad is offset from a corresponding axis of the platen. 
     
     
         5 . The method of  claim 1 , wherein the one or more sensors comprise at least one of a light sensor or electrical sensor. 
     
     
         6 . The method of  claim 1 , wherein each of the one or more sensor paths is associated with a corresponding sensor of each of the one or more sensors. 
     
     
         7 . The method of  claim 1 , wherein each of the one or more sensors share at least one of the one or more sensors paths. 
     
     
         8 . The method of  claim 7 , wherein the one or more sensors pass along at least one of the one or more sensor paths at different times. 
     
     
         9 . The method of  claim 1 , wherein the one or more sensor paths maximize a signal quality associated with one or more of the one or more sensors. 
     
     
         10 . The method of  claim 9 , wherein maximizing the signal quality is determined by the one or more sensor paths crossing a maximum number of centers of dies. 
     
     
         11 . The method of  claim 9 , wherein maximizing the signal quality is determined by the one or more sensor paths crossing a maximum number of boundaries between dies substantially perpendicularly. 
     
     
         12 . A system for polishing a substrate, the system comprising:
 a carrier head configured to accept a substrate;   a platen;   one or more processors; and   one or more non-transitory computer-readable media comprising instructions that when executed by the one or more processors cause the system to:
 receive the substrate in a known alignment in the carrier head of a polishing system for a polishing process, wherein the polishing process causes the substrate in the carrier head to be polished by a polishing pad on the platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths relative to the known alignment of the substrate; 
 cause the carrier head to move to a first position based on the one or more predetermined sensor paths; 
 cause the platen to move to a second position based on the one or more predetermined sensor paths; and 
 cause the substrate to rotate relative to the platen such that the one or more sensors pass along the one or more predetermined sensor paths. 
   
     
     
         13 . The system of  claim 12 , wherein a groove of the polishing pad is offset from a corresponding axis of the platen. 
     
     
         14 . The system of  claim 12 , wherein the one or more sensors comprise at least one of a light detector or electrical detector. 
     
     
         15 . The system of  claim 12 , wherein each of the one or more sensor paths is associated with a corresponding sensor of each of the one or more sensors. 
     
     
         16 . The system of  claim 12 , wherein each of the one or more sensors share at least one of the one or more sensors paths. 
     
     
         17 . One or more non-transitory computer-readable media comprising instructions that, when executed by one or more processors, cause the one or more processors to perform operations to:
 receive a substrate in a known alignment in a carrier head of a polishing station for a polishing process, wherein the polishing process causes the substrate in the carrier head to be polished by a polishing pad on a platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths relative to the known alignment of the substrate;   cause the carrier head to move to a first position based on the one or more predetermined sensor paths;   cause the platen to move to a second position based on the one or more predetermined sensor paths; and   cause the substrate to rotate relative to the platen such that the one or more sensors pass along the one or more predetermined sensor paths.   
     
     
         18 . The one or more non-transitory computer-readable media of  claim 17 , wherein the one or more sensor paths maximize a signal quality associated with one or more of the one or more sensors. 
     
     
         19 . The one or more non-transitory computer-readable media of  claim 18 , wherein maximizing the signal quality is determined by the one or more sensor paths crossing a maximum number of centers of dies. 
     
     
         20 . The one or more non-transitory computer-readable media of  claim 18 , wherein maximizing the signal quality is determined by the one or more sensor paths crossing a maximum number of boundaries between dies substantially perpendicularly.