Chemical mechanical polishing system and controlling method thereof

A chemical mechanical polishing (CMP) device for a wafer from which semiconductor devices are formed, the CMP device comprising:

• a platen and a polishing pad disposed on a first surface of the platen in a configuration that performs a CMP process on a wafer;
• a head that rotates and vibrates the wafer on the polishing pad;
• a retainer ring disposed at an edge of the polishing pad and configured to prevent the wafer from dislodging from the head during the CMP process;
• and
• a control unit configured to:
• calculate a movement trajectory on the polishing pad of at least one reference point on a surface of the retainer ring in contact with the polishing pad and a center point of the retainer ring during the CMP process;
• calculate a sliding distance of the at least one reference point and a trajectory distribution density of the movement trajectory of the center point;
• predict a wear profile of the retainer ring based on the sliding distance and the trajectory distribution density;
• and
• control process conditions of the CMP process based on the wear profile.