One aspect of the present invention relates to an in-line system for monitoring and optimizing an on-going CMP process in order to determine a CMP process endpoint comprising a wafer, wherein the wafer is subjected to the CMP process; a CMP process monitoring system for generating a signature related to wafer dimensions for the wafer subjected to the CMP process; and a signature library to which the generated signature is compared to determine a state of the wafer. Another aspect relates to an in-line method for monitoring and optimizing an on-going CMP process involving providing a wafer, wherein the wafer is subjected to a CMP process; generating a signature associated with the wafer; comparing the generated signature to a signature library to determine a state of the wafer; and using a closed-loop feedback control system for modifying the on-going CMP process according to the determined state of the wafer.